Combo discount price includes 1 Lower and 1 Aluminum Upper vise block Made in the USA Lower Block will work with or without magazine latch installed Upper block is machined from a solid block of aluminum for strength and precision fit Works on delta ring or free float style uppers Magazine lock is on both side of the lower block so it will lock going into the top or through the bottom. It also has a rigid stop so a "bare" receiver can be held in a vise without sliding down and hitting the metal vise jaws.