Ducts for 2013 GMC Sierra 2500 HD
Categories
- Aero Ground Effects & Body Kits
- Back Panel
- Body Mounting
- Box Rails
- Brackets, Flanges & Hangers
- Bumper
- Bumper & Components - Front
- Bumper & Components - Rear
- Bushings
- Cab Assembly
- Center Console
- Cluster & Switches
- Console
- Control Cables
- Control Modules
- Cowl
- Dashboard
- Door & Components
- Doors
- Ducts
- Exterior Trim - Cab
- Exterior Trim - Fender
- Exterior Trim - Front Door
- Exterior Trim - Hood
- Exterior Trim - Pick UP Box
- Exterior Trim - Rear Door
- Fender & Components
- Fenders
- Floor
- Floor - Cab
- Frame
- Frame & Components
- Front Door
- Front Seat Components
- Gaskets & Sealing Systems
- Glass - Front Door
- Glass - Rear Door
- Glass - Windshield
- Glass & Hardware - Back
- Glass, Windows & Related Components
- Glove Box
- Grille
- Grille & Components
- Hardware, Fasteners & Fittings
- Hood
- Hood & Components
- Horns
- Information Labels
- Instrument Panel
- Interior Trim - Cab
- Interior Trim - Front Door
- Interior Trim - Rear Door
- Interior Trim - Roof
- Jack & Components
- Labels
- Lock & Hardware
- Luggage Carrier
- Master Cylinder - Components On Dash Panel
- Mirrors
- Outside Mirrors
- Overhead Console
- Pick UP Box Components
- Quarter Panel
- Radiator Support
- Rear Body
- Rear Door
- Rear Seat Components
- Reveal Moldings
- Rocker
- Rocker Panel
- Roof
- Roof & Components
- Roof Lamps
- Running Board
- Seat Belt
- Seats
- Sensors
- Side Body
- Side Pillar
- Sound System
- Spare Tire Carrier
- Splash Shields
- Steering Wheel
- Sunroof
- Switches, Solenoids & Actuators
- Tail Gate
- Tailgate
- Tailgate & Midgate
- Trailer Hitch Components
- Truck Box
- Truck Cab
- Uniside
- Wiper & Washer Components
- Wire, Cable & Related Components
- ABS Components
- Brackets, Flanges & Hangers
- Brake Components
- Brake Hydraulics
- Control Modules
- Disc Pads & Brake Shoes
- Drums & Rotors
- Front Brakes
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Hoses & Pipes
- Parking Brake
- Rear Brakes
- Sensors
- Stability Control
- Switches, Solenoids & Actuators
- Vacuum Booster
- ABS Components
- Air Bag Components
- Air Bag System
- Alternator
- Alternator/Generator & Related Components
- Antenna & Radio
- Anti-Theft System
- Automatic Transmission
- Battery
- Battery & Related Components
- Body Wiring Harness & Components
- Brackets, Flanges & Hangers
- Bulbs - Chassis
- Bushings
- Combination Lamps
- Communication System Components
- Control Modules
- Daytime Running Lamps
- Diesel Components
- Driver Information Center
- Electrical Components
- Electrical Connectors
- Entertainment System Components
- Flasher Units, Fuses, & Circuit Breakers
- Fog Lamps
- Front Door
- Front Seat Belts
- Fuse & Relay
- Glass, Windows & Related Components
- Hardware, Fasteners & Fittings
- Headlamp Components
- Heated Seats
- High Mount Lamps
- Horn
- Identification Lamps
- Ignition Lock
- Ignition System
- Instruments & Gauges
- Keyless Entry Components
- License Lamps
- Lighting - Exterior
- Lighting - Interior
- Lumbar Control Seats
- Mirrors
- Mobile Multi-Media
- Navigation System
- Parking Aid
- Power Outlets
- Power Seats
- Powertrain Control
- Rear Door
- Rear Seat Belts
- Relays
- Senders
- Sensors
- Starter
- Starter & Related Components
- Steering Column
- Steering Wheel
- Sunroof
- Switches
- Switches, Solenoids & Actuators
- Tire Pressure Monitor Components
- Wipers
- Wire, Cable & Related Components
- Wiring Harness
- Air Intake
- Bearings
- Brackets, Flanges & Hangers
- Control Modules
- Cylinder Block Components
- Engine
- Engine & Trans Mounting
- Engine Appearance Cover
- Engine Parts
- Filters
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Mounts
- Oil Pan
- Oil Pump
- Pumps
- Switches, Solenoids & Actuators
- Valve Train Components
- Wire, Cable & Related Components
- A/C Accumulator/Receiver Drier
- A/C Clutch & Compressor
- A/C Condenser & Evaporator
- A/C Flow Restrictors
- Automatic Temperature Controls
- Auxiliary Heater & AC
- Blower Motor & Fan
- Brackets, Flanges & Hangers
- Condenser, Compressor & Lines
- Control Modules
- Controls
- Electrical Connectors
- Evaporator & Heater Components
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Heater
- Hoses & Pipes
- HVAC Case
- Motors, Core, Case & Related Components
- Relays
- Sensors
- Switches, Solenoids & Actuators
- Temperature Controls & Related Components
- Wire, Cable & Related Components
- Bearings
- Brackets, Flanges & Hangers
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Lower Components
- P/S Pump & Hoses
- Power Steering Hoses, Pumps, & Related Components
- Pump & Hoses
- Sensors
- Shroud, Switches & Levers
- Steering Column
- Steering Gear & Linkage
- Steering Wheel
- Steering Wheel & Trim
- Steering, Gear & Related Components
- Wire, Cable & Related Components
- Aero Ground Effects & Body Kits
- Back Panel
- Body Mounting
- Box Rails
- Brackets, Flanges & Hangers
- Bumper
- Bumper & Components - Front
- Bumper & Components - Rear
- Bushings
- Cab Assembly
- Center Console
- Cluster & Switches
- Console
- Control Cables
- Control Modules
- Cowl
- Dashboard
- Door & Components
- Doors
- Ducts
- Exterior Trim - Cab
- Exterior Trim - Fender
- Exterior Trim - Front Door
- Exterior Trim - Hood
- Exterior Trim - Pick UP Box
- Exterior Trim - Rear Door
- Fender & Components
- Fenders
- Floor
- Floor - Cab
- Frame
- Frame & Components
- Front Door
- Front Seat Components
- Gaskets & Sealing Systems
- Glass - Front Door
- Glass - Rear Door
- Glass - Windshield
- Glass & Hardware - Back
- Glass, Windows & Related Components
- Glove Box
- Grille
- Grille & Components
- Hardware, Fasteners & Fittings
- Hood
- Hood & Components
- Horns
- Information Labels
- Instrument Panel
- Interior Trim - Cab
- Interior Trim - Front Door
- Interior Trim - Rear Door
- Interior Trim - Roof
- Jack & Components
- Labels
- Lock & Hardware
- Luggage Carrier
- Master Cylinder - Components On Dash Panel
- Mirrors
- Outside Mirrors
- Overhead Console
- Pick UP Box Components
- Quarter Panel
- Radiator Support
- Rear Body
- Rear Door
- Rear Seat Components
- Reveal Moldings
- Rocker
- Rocker Panel
- Roof
- Roof & Components
- Roof Lamps
- Running Board
- Seat Belt
- Seats
- Sensors
- Side Body
- Side Pillar
- Sound System
- Spare Tire Carrier
- Splash Shields
- Steering Wheel
- Sunroof
- Switches, Solenoids & Actuators
- Tail Gate
- Tailgate
- Tailgate & Midgate
- Trailer Hitch Components
- Truck Box
- Truck Cab
- Uniside
- Wiper & Washer Components
- Wire, Cable & Related Components
- ABS Components
- Brackets, Flanges & Hangers
- Brake Components
- Brake Hydraulics
- Control Modules
- Disc Pads & Brake Shoes
- Drums & Rotors
- Front Brakes
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Hoses & Pipes
- Parking Brake
- Rear Brakes
- Sensors
- Stability Control
- Switches, Solenoids & Actuators
- Vacuum Booster
- ABS Components
- Air Bag Components
- Air Bag System
- Alternator
- Alternator/Generator & Related Components
- Antenna & Radio
- Anti-Theft System
- Automatic Transmission
- Battery
- Battery & Related Components
- Body Wiring Harness & Components
- Brackets, Flanges & Hangers
- Bulbs - Chassis
- Bushings
- Combination Lamps
- Communication System Components
- Control Modules
- Daytime Running Lamps
- Diesel Components
- Driver Information Center
- Electrical Components
- Electrical Connectors
- Entertainment System Components
- Flasher Units, Fuses, & Circuit Breakers
- Fog Lamps
- Front Door
- Front Seat Belts
- Fuse & Relay
- Glass, Windows & Related Components
- Hardware, Fasteners & Fittings
- Headlamp Components
- Heated Seats
- High Mount Lamps
- Horn
- Identification Lamps
- Ignition Lock
- Ignition System
- Instruments & Gauges
- Keyless Entry Components
- License Lamps
- Lighting - Exterior
- Lighting - Interior
- Lumbar Control Seats
- Mirrors
- Mobile Multi-Media
- Navigation System
- Parking Aid
- Power Outlets
- Power Seats
- Powertrain Control
- Rear Door
- Rear Seat Belts
- Relays
- Senders
- Sensors
- Starter
- Starter & Related Components
- Steering Column
- Steering Wheel
- Sunroof
- Switches
- Switches, Solenoids & Actuators
- Tire Pressure Monitor Components
- Wipers
- Wire, Cable & Related Components
- Wiring Harness
- Air Intake
- Bearings
- Brackets, Flanges & Hangers
- Control Modules
- Cylinder Block Components
- Engine
- Engine & Trans Mounting
- Engine Appearance Cover
- Engine Parts
- Filters
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Mounts
- Oil Pan
- Oil Pump
- Pumps
- Switches, Solenoids & Actuators
- Valve Train Components
- Wire, Cable & Related Components
- A/C Accumulator/Receiver Drier
- A/C Clutch & Compressor
- A/C Condenser & Evaporator
- A/C Flow Restrictors
- Automatic Temperature Controls
- Auxiliary Heater & AC
- Blower Motor & Fan
- Brackets, Flanges & Hangers
- Condenser, Compressor & Lines
- Control Modules
- Controls
- Electrical Connectors
- Evaporator & Heater Components
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Heater
- Hoses & Pipes
- HVAC Case
- Motors, Core, Case & Related Components
- Relays
- Sensors
- Switches, Solenoids & Actuators
- Temperature Controls & Related Components
- Wire, Cable & Related Components
- Bearings
- Brackets, Flanges & Hangers
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Lower Components
- P/S Pump & Hoses
- Power Steering Hoses, Pumps, & Related Components
- Pump & Hoses
- Sensors
- Shroud, Switches & Levers
- Steering Column
- Steering Gear & Linkage
- Steering Wheel
- Steering Wheel & Trim
- Steering, Gear & Related Components
- Wire, Cable & Related Components
Browse Categories
Select category
- Aero Ground Effects & Body Kits
- Back Panel
- Body Mounting
- Box Rails
- Brackets, Flanges & Hangers
- Bumper
- Bumper & Components - Front
- Bumper & Components - Rear
- Bushings
- Cab Assembly
- Center Console
- Cluster & Switches
- Console
- Control Cables
- Control Modules
- Cowl
- Dashboard
- Door & Components
- Doors
- Ducts
- Exterior Trim - Cab
- Exterior Trim - Fender
- Exterior Trim - Front Door
- Exterior Trim - Hood
- Exterior Trim - Pick UP Box
- Exterior Trim - Rear Door
- Fender & Components
- Fenders
- Floor
- Floor - Cab
- Frame
- Frame & Components
- Front Door
- Front Seat Components
- Gaskets & Sealing Systems
- Glass - Front Door
- Glass - Rear Door
- Glass - Windshield
- Glass & Hardware - Back
- Glass, Windows & Related Components
- Glove Box
- Grille
- Grille & Components
- Hardware, Fasteners & Fittings
- Hood
- Hood & Components
- Horns
- Information Labels
- Instrument Panel
- Interior Trim - Cab
- Interior Trim - Front Door
- Interior Trim - Rear Door
- Interior Trim - Roof
- Jack & Components
- Labels
- Lock & Hardware
- Luggage Carrier
- Master Cylinder - Components On Dash Panel
- Mirrors
- Outside Mirrors
- Overhead Console
- Pick UP Box Components
- Quarter Panel
- Radiator Support
- Rear Body
- Rear Door
- Rear Seat Components
- Reveal Moldings
- Rocker
- Rocker Panel
- Roof
- Roof & Components
- Roof Lamps
- Running Board
- Seat Belt
- Seats
- Sensors
- Side Body
- Side Pillar
- Sound System
- Spare Tire Carrier
- Splash Shields
- Steering Wheel
- Sunroof
- Switches, Solenoids & Actuators
- Tail Gate
- Tailgate
- Tailgate & Midgate
- Trailer Hitch Components
- Truck Box
- Truck Cab
- Uniside
- Wiper & Washer Components
- Wire, Cable & Related Components
- ABS Components
- Brackets, Flanges & Hangers
- Brake Components
- Brake Hydraulics
- Control Modules
- Disc Pads & Brake Shoes
- Drums & Rotors
- Front Brakes
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Hoses & Pipes
- Parking Brake
- Rear Brakes
- Sensors
- Stability Control
- Switches, Solenoids & Actuators
- Vacuum Booster
- ABS Components
- Air Bag Components
- Air Bag System
- Alternator
- Alternator/Generator & Related Components
- Antenna & Radio
- Anti-Theft System
- Automatic Transmission
- Battery
- Battery & Related Components
- Body Wiring Harness & Components
- Brackets, Flanges & Hangers
- Bulbs - Chassis
- Bushings
- Combination Lamps
- Communication System Components
- Control Modules
- Daytime Running Lamps
- Diesel Components
- Driver Information Center
- Electrical Components
- Electrical Connectors
- Entertainment System Components
- Flasher Units, Fuses, & Circuit Breakers
- Fog Lamps
- Front Door
- Front Seat Belts
- Fuse & Relay
- Glass, Windows & Related Components
- Hardware, Fasteners & Fittings
- Headlamp Components
- Heated Seats
- High Mount Lamps
- Horn
- Identification Lamps
- Ignition Lock
- Ignition System
- Instruments & Gauges
- Keyless Entry Components
- License Lamps
- Lighting - Exterior
- Lighting - Interior
- Lumbar Control Seats
- Mirrors
- Mobile Multi-Media
- Navigation System
- Parking Aid
- Power Outlets
- Power Seats
- Powertrain Control
- Rear Door
- Rear Seat Belts
- Relays
- Senders
- Sensors
- Starter
- Starter & Related Components
- Steering Column
- Steering Wheel
- Sunroof
- Switches
- Switches, Solenoids & Actuators
- Tire Pressure Monitor Components
- Wipers
- Wire, Cable & Related Components
- Wiring Harness
- Air Intake
- Bearings
- Brackets, Flanges & Hangers
- Control Modules
- Cylinder Block Components
- Engine
- Engine & Trans Mounting
- Engine Appearance Cover
- Engine Parts
- Filters
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Mounts
- Oil Pan
- Oil Pump
- Pumps
- Switches, Solenoids & Actuators
- Valve Train Components
- Wire, Cable & Related Components
- A/C Accumulator/Receiver Drier
- A/C Clutch & Compressor
- A/C Condenser & Evaporator
- A/C Flow Restrictors
- Automatic Temperature Controls
- Auxiliary Heater & AC
- Blower Motor & Fan
- Brackets, Flanges & Hangers
- Condenser, Compressor & Lines
- Control Modules
- Controls
- Electrical Connectors
- Evaporator & Heater Components
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Heater
- Hoses & Pipes
- HVAC Case
- Motors, Core, Case & Related Components
- Relays
- Sensors
- Switches, Solenoids & Actuators
- Temperature Controls & Related Components
- Wire, Cable & Related Components
- Bearings
- Brackets, Flanges & Hangers
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Lower Components
- P/S Pump & Hoses
- Power Steering Hoses, Pumps, & Related Components
- Pump & Hoses
- Sensors
- Shroud, Switches & Levers
- Steering Column
- Steering Gear & Linkage
- Steering Wheel
- Steering Wheel & Trim
- Steering, Gear & Related Components
- Wire, Cable & Related Components
- Aero Ground Effects & Body Kits
- Back Panel
- Body Mounting
- Box Rails
- Brackets, Flanges & Hangers
- Bumper
- Bumper & Components - Front
- Bumper & Components - Rear
- Bushings
- Cab Assembly
- Center Console
- Cluster & Switches
- Console
- Control Cables
- Control Modules
- Cowl
- Dashboard
- Door & Components
- Doors
- Ducts
- Exterior Trim - Cab
- Exterior Trim - Fender
- Exterior Trim - Front Door
- Exterior Trim - Hood
- Exterior Trim - Pick UP Box
- Exterior Trim - Rear Door
- Fender & Components
- Fenders
- Floor
- Floor - Cab
- Frame
- Frame & Components
- Front Door
- Front Seat Components
- Gaskets & Sealing Systems
- Glass - Front Door
- Glass - Rear Door
- Glass - Windshield
- Glass & Hardware - Back
- Glass, Windows & Related Components
- Glove Box
- Grille
- Grille & Components
- Hardware, Fasteners & Fittings
- Hood
- Hood & Components
- Horns
- Information Labels
- Instrument Panel
- Interior Trim - Cab
- Interior Trim - Front Door
- Interior Trim - Rear Door
- Interior Trim - Roof
- Jack & Components
- Labels
- Lock & Hardware
- Luggage Carrier
- Master Cylinder - Components On Dash Panel
- Mirrors
- Outside Mirrors
- Overhead Console
- Pick UP Box Components
- Quarter Panel
- Radiator Support
- Rear Body
- Rear Door
- Rear Seat Components
- Reveal Moldings
- Rocker
- Rocker Panel
- Roof
- Roof & Components
- Roof Lamps
- Running Board
- Seat Belt
- Seats
- Sensors
- Side Body
- Side Pillar
- Sound System
- Spare Tire Carrier
- Splash Shields
- Steering Wheel
- Sunroof
- Switches, Solenoids & Actuators
- Tail Gate
- Tailgate
- Tailgate & Midgate
- Trailer Hitch Components
- Truck Box
- Truck Cab
- Uniside
- Wiper & Washer Components
- Wire, Cable & Related Components
- ABS Components
- Brackets, Flanges & Hangers
- Brake Components
- Brake Hydraulics
- Control Modules
- Disc Pads & Brake Shoes
- Drums & Rotors
- Front Brakes
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Hoses & Pipes
- Parking Brake
- Rear Brakes
- Sensors
- Stability Control
- Switches, Solenoids & Actuators
- Vacuum Booster
- ABS Components
- Air Bag Components
- Air Bag System
- Alternator
- Alternator/Generator & Related Components
- Antenna & Radio
- Anti-Theft System
- Automatic Transmission
- Battery
- Battery & Related Components
- Body Wiring Harness & Components
- Brackets, Flanges & Hangers
- Bulbs - Chassis
- Bushings
- Combination Lamps
- Communication System Components
- Control Modules
- Daytime Running Lamps
- Diesel Components
- Driver Information Center
- Electrical Components
- Electrical Connectors
- Entertainment System Components
- Flasher Units, Fuses, & Circuit Breakers
- Fog Lamps
- Front Door
- Front Seat Belts
- Fuse & Relay
- Glass, Windows & Related Components
- Hardware, Fasteners & Fittings
- Headlamp Components
- Heated Seats
- High Mount Lamps
- Horn
- Identification Lamps
- Ignition Lock
- Ignition System
- Instruments & Gauges
- Keyless Entry Components
- License Lamps
- Lighting - Exterior
- Lighting - Interior
- Lumbar Control Seats
- Mirrors
- Mobile Multi-Media
- Navigation System
- Parking Aid
- Power Outlets
- Power Seats
- Powertrain Control
- Rear Door
- Rear Seat Belts
- Relays
- Senders
- Sensors
- Starter
- Starter & Related Components
- Steering Column
- Steering Wheel
- Sunroof
- Switches
- Switches, Solenoids & Actuators
- Tire Pressure Monitor Components
- Wipers
- Wire, Cable & Related Components
- Wiring Harness
- Air Intake
- Bearings
- Brackets, Flanges & Hangers
- Control Modules
- Cylinder Block Components
- Engine
- Engine & Trans Mounting
- Engine Appearance Cover
- Engine Parts
- Filters
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Mounts
- Oil Pan
- Oil Pump
- Pumps
- Switches, Solenoids & Actuators
- Valve Train Components
- Wire, Cable & Related Components
- A/C Accumulator/Receiver Drier
- A/C Clutch & Compressor
- A/C Condenser & Evaporator
- A/C Flow Restrictors
- Automatic Temperature Controls
- Auxiliary Heater & AC
- Blower Motor & Fan
- Brackets, Flanges & Hangers
- Condenser, Compressor & Lines
- Control Modules
- Controls
- Electrical Connectors
- Evaporator & Heater Components
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Heater
- Hoses & Pipes
- HVAC Case
- Motors, Core, Case & Related Components
- Relays
- Sensors
- Switches, Solenoids & Actuators
- Temperature Controls & Related Components
- Wire, Cable & Related Components
- Bearings
- Brackets, Flanges & Hangers
- Gaskets & Sealing Systems
- Hardware, Fasteners & Fittings
- Lower Components
- P/S Pump & Hoses
- Power Steering Hoses, Pumps, & Related Components
- Pump & Hoses
- Sensors
- Shroud, Switches & Levers
- Steering Column
- Steering Gear & Linkage
- Steering Wheel
- Steering Wheel & Trim
- Steering, Gear & Related Components
- Wire, Cable & Related Components
Ducts for 2013 GMC Sierra 2500 HD
6
- Instrument Panel Air DuctGMCadillac, front. Escalade, front. Without uplevel slt package. with auto temp cntrl. Escalade EXT. 2008-09. Sedan, chevrolet & gmc, front, with auto temp cntrl. (Unavailable)
- Instrument Panel Air DuctGMWithout auto ac. Avalanche, with auto temp cntrl. Cadillac, front. Escalade, front, front. Without uplevel slt package. with auto temp cntrl. Escalade EXT. With electronic ac. Ext & crew cab. 2008-09. Sedan, chevrolet & gmc, front, with auto temp cntrl. (Unavailable)
- Instrument Panel Air DuctGMWith uplevel slt package. Tahoe & Yukon, front, 2nd design. Avalanche. Tahoe & Yukon, front, 1st design. Sedan, chevrolet & gmc, front. (Unavailable)
- Instrument Panel Air DuctGMWithout uplevel slt package. without auto temp cntrl. (Unavailable)
No.
Part # / Description / Price
Price
6
Lower Air Duct 
GM
GM Positions: Left
Description: Cadillac, front. Escalade, front. Without uplevel slt package. with auto temp cntrl. Escalade EXT. 2008-09. Sedan, chevrolet & gmc, front, with auto temp cntrl.
6
Lower Air Duct GM
GM Positions: Right
Description: Without auto ac. Avalanche, with auto temp cntrl. Cadillac, front. Escalade, front, front. Without uplevel slt package. with auto temp cntrl. Escalade EXT. With electronic ac. Ext & crew cab. 2008-09. Sedan, chevrolet & gmc, front, with auto temp cntrl.
6
Defroster Duct GM
GM Positions: Front right
Description: With uplevel slt package. Tahoe & Yukon, front, 2nd design. Avalanche. Tahoe & Yukon, front, 1st design. Sedan, chevrolet & gmc, front.
7
Air Deflector GM
GM Positions: Right outer
Description: Tahoe & Yukon, front, outer. Avalanche, outer. With uplevel slt package. outer. Sedan, chevrolet & gmc, front, outer.