IMI Defense Lower Vice Block Black. The Upper Receiver Vice Block completes the set and provides a safe solution that holds the rifle for assembly clean and repair. Features of IMI Defense Lower Vice Block Use In Seconds Easy to work on your rifle without causing damage. The heavy-duty blocks allow you to firmly clamp M16/AR15 receiver halves in a vise without risk of crushing twisting or otherwise distorting them when applying vise pressure or torquing the barrel nut. Keeps your rifle secure for safe effective cleaning assembly and repair. Unbreakable urethane vise block takes all the clamping force so your expensive lower receiver wont be damaged or distorted. Insert block into the magazine housing from the top or bottom then clamp the other end in your bench vise. The magazine catch locks to the block safely and securely holding the rifle for assembly disassembly cleaning or repair. Will not mar or scratch the finish. Package Contents: IMI Defense Lower Vice Block IMI Defense IMI-ZT001: Lower Vice Block Black