The BT65-NC model Atlas Bipod is part of their CAL Series. The "NC" stands for "No Clamp," meaning it requires any 17S size mount in order to attach to a firearm. The interface to install a clamp has a two hole pattern of 1.100" with 10/32 threads. It will also mount directly to their BT19 AI Spigot or BT70 M-LOK Adapter.The BT65-NC is comprised of 6061-T6 aluminum that is Mil-Spec Type III hard coat anodized with treated stainless steel components. Includes two 10-32 x 3/8" flathead socket screws. Available in black only. FeaturesHeight Range: 4.8 - 9.2" (6.4" at 90deg)Preloaded Cant: 63 degreesPosition Button 0.5" diameter5 leg positions: 0, 45, 90, 135 & 180 degreesNon-Rotating Legs: outer leg does not rotate around inner legLarger, stronger inner legsWeight: 12.7 ouncesFootprint: 9- 12.5"