The Aimpoint CompM4 Accucam QD Cantilever Mounting Base provides you with two inches of additional eye relief, while also providing space behind the CompM4 for an Aimpoint 3X Magnifier or PVS-14 Monocular. Tactical flexibility is highly valued in urban combat, and the New Aimpoint CompM4 QD Mount fills that need. This New Base allows the end user to quickly switch between optics and still maintain "on target" repeatability. The Aimpoint CompM4 base is a rugged optic; however, if by chance it should fail, the end user can choose between quickly deploying the weapons back-up iron sight and sighting through the CompM4, or quickly remove the scope and deploy the back-up iron sight. By using the Aimpoint CompM4 Cantilever Ring Mounting Base, the optic can quickly be installed on a dovetail rail by rotating the Accucam Cam Lever to the locked position. It can then be quickly removed by rotating the Accucam Cam Lever to the unlocked position. The unique cam design is fully adjustable to fit both Weaver and MIL-STD-1913 dovetails, and allows you to adjust the tension to accommodate out-of-spec or worn dovetails. Not recommended for .50 BMG or lightweight machine guns. In tests, the Accucam Locking Lever System has shown to be repeatable to 1/2 MOA. The unique finger loop design is easily operated, even with a gloved hand, and the rounded design is ergonomic and virtually snag-proof. The New GG&G Aimpoint CompM4 Mount is manufactured from solid billet 6061 T6 aluminum alloy and Type III hard-coat anodized matte black to meet mil-spec. The Accucam mechanism is manufactured from solid billet 4140 steel and manganese phosphated matte black to mil-spec. The Comp M4 QD scope base, along with all our other products, is manufactured in the U.S.A.