The derailleur is brand new and has never been mounted on a bicycle. It is part of a bulk order (OEM) from SRAM so there is no retail. What's in the box!?!? SRAM GX AXS Eagle rear derailleur and owner's manual. 

This is a no nonsense rear derailleur that can handle all your riding nonsense. Wanna shift gears while powering up a rock garden? Wanna get rowdy in the park? GX is fine choice. 

Tech note: This is not for Transmission T-Type flattop chain drivetrains. This is for Eagle drivetrains from before Transmission flattop T-Type drivetrains.

Specs:

For SRAM Eagle 12 speed drivetrains

Overload Clutch protection

AXS technology 

10-50 and 10-52 cassette compatible