This is a used kit for an Aimpoint Comp M2 M68 Close Combat Optic CCO Double Battery Holder Assembly. This kit allows the old bushing currently on M68 to be replaced with a battery extender assembly. While only one battery will be in use at a time, you can now conveniently carry a spare, with the backup ready to be installed whenever you need it. These will fit on the M3, as well. NOTE: These do not fit the original Aimpoint CompM XD, which was from 1997 and discontinued in 2000.
The cap is steel and well worn. These have been removed from used CompM2 / M68 optics. The compartment held a spare battery and with its rubber O-ring was a water proof compartment. Charlie's has taken this off of a working older used optic, and you should expect the black oxide on the steel to be well worn and showing white steel. No rust, and in perfect working order. The part was last made around 2012 (+/-), for reference.
Note: photo shows two parts, so that you may see both sides, but for sale is one part.
Manufacturer's Part Number 11277, also seen referred to as 9000SC-NV