ELEMENT LR's QD CompM Standard mount (also known as M68-CCO). The standard in the industry. The base has a built-in watertight storage compartment for an extra battery...comes in handy.
Fits Aimpoint Comp M Series; ML2, M2, ML3, and M3 red dot optics
another fit other diameter 30mm scope .
Fits for 20mm Standard Rail System
Dual Throw Lever with One Safety Lock Quick release nuts allow fast and secure attachment