This set of 4 in line right handed official Fender Standard/Highway One Series Bass Tuners are used on Highway One, American Special, American Deluxe, Blacktop and Standard series basses, they are used on many of the made in Mexico Fender bass guitars. The 4 screws per tuner (included) fix it to the back of the headstock and the knurled push fit bushing secures the string post on the front of the headstock.