Below there is a list with the links of the items that have been tested and confirmed to work with the SUB-2000 CQB! All Internal SUB-2000 UpgradesRapid Deployment Latch (RDL)Buttstock PadAll 3 Charging Handle Options:Double Finger Charging HandleRecoilless Charging HandleSkeletonized Charging HandleBolt Tube Cover It might be a little tight when folding the firearm but it fits Now here is the bad news below... Unfortunately the Muzzle Brake, Optic Mount, Rear Folding Sight and Shell Deflector will not fit/function with the CQB. Posted by M*CARBO Friday, September 9, 2022 0 Comments Add a Comment to this Post You must be logged in to post comments.