The Atlas Accuracy International Spigot (AAIS) Part number BT19 – 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 is proudly made in the USA