The American Defense Recon-H Quick-Release Scope Mount is made for putting high power glass onto a flattop style AR-15. The AD-RECON-H is taller than other Recon mount models. It is precision machined from 6061 T6 aluminum and finished in hard coat T3 Mil-Spec anodize. It features the patent pending Auto Lock Lever system to accommodate both in spec and out of spec rail systems. Height (Center line of scope tube to top of mounting base): 1"=1.840"30mm=1.930"Operation Instructions: Make sure your firearm is unloaded and the muzzle is pointed in a safe directionFamiliarize yourself with the mount and it's partsUnlock the mount. To do this, depress the lock button and move the lever 180 degrees to the unlocked position Install assembly onto rail and move lever to the locked positionCheck tension to close. Correct tension is the maximum amount of tension you can apply with your hand to move the lever to the closed position. A little judgment and personal preference is nee...