Sight mount for Aimpoint® CompM4 / CompM4S (M68 / CCO) Red Dot Reflex Sights. HK 416 / 417 - Gas Piston Upper CompatibleLower 3rd Co-witness: Front sight post tip in lower 3rd of sight picture. General Features:? For use with Aimpoint® CompM4/CompM4S (M68/CCO) Red Dot Reflex Sights? Retains Zero under extensive live fire usage and while subjected to harsh mechanical stresses: .01 MOA? Returns to Zero following repeated removal-remount cycles during extensive live fire usage: Value: .01 MOA [Lab Tested] < .20 MOA [Live Fire]? Adjustable to Out-of-Spec / Worn M1913 Picatinny Rails? Auto-Locking Quick Detach™ (ALQD™) Lever System? Non-Abrading / Gouging Picatinny Rail Lockdown Feature. GDI CM4-OSM Optic Sight Mount CM4M