The Atlas Accuracy International Spigot (AAIS) is designed for use with the BT10-NC Atlas Bipod that mounts directly to the AAIS, which plugs into the Accuracy International AI/AICS stocks utilizing the factory retention/release mechanism. The AAIS is constructed from 6061T6 Aluminum with a type II hard coat anodize mated with an alloy steel Spigot that is finished with a Manganese Phosphate. The AAIS weighs approximately 4.7 ounces.Notes:When installing the BT-19 Please be sure to Loosen the Tension Nut up as much as possible before inserting the Spigot into the stock. Push Spigot into the receptacle using the Tension Knob until there is a good solid Click of the spigot locking into place, then tighten the Tension Knob.