The Knights Armament D Collar adds significant functional utility. The titanium (suggested for plastic housings), the D Collar provides a rigid and protective centrifugal anchor point for various aftermarket accessories while providing crush resistance to the objective lens bore. The D Collar’s eccentric design also acts as an objective lens stop, eliminating any internal retention rings which disallow objective lens repair, cleaning or assembly ease. The D Collar allows the removal, replacement and maintenance of the objective lens assemble without (typical) disassembly of the entire PVS-14 with an internal retention collar.