This kit contains the semi auto bolt, internal parts and instructions needed to convert an original full auto lower assembly into an ATF approved semi auto configuration. It is compatible with our tube (M56 SAT) and will work with either 9mm Luger or 7.62 x 25 TOK ammunition. It also converts the selector switch into a safety. The builder will need to make the receiver using one of our blanks. The builder is responsible for following all ATF guidelines whether it is built as a rifle, pistol, or Short Barreled Rifle.