This is a set of steel saddles that can be used to prevent strings from falling off on retro-tone Jazzmasters, Jaguars, etc. The main unit only is for sale. The manufacturer's description is as follows: This is a kit that includes height-adjustable steel bridge saddles for Jazzmaster/Jaguar/Mustang and various screws. Recommended for those seeking a rock-driven sound. The V-shaped string grooves of the steel saddles can accommodate string vibrations regardless of string thickness, providing optimal sustain. There is no need to worry about strings falling off, which has been a concern for users.