The 2 hole Picatinny Rail Clamp is CNC made from 6061 alum. and has a Class II Black Anodized finish. 10/32 bolts are included. Proper torque is 18 inch pounds (use the shorter end of the Allen wrench to tighten). 1.00 in length. The side with the threads is thicker to add strength and a form tap is used to maximize strength and thread surfaces. NOTE: One Clamp is Included With any Rail Mounted ABR