Grover 133NK Deluxe Guitar Machines with Keystone Button - Guitar Machine Heads, 3 + 3 - Nickel, Grover Deluxe machine heads for guitar, vintage style, closed gear, ratio: 15:1, 6 pieces: 3x left, 3x right, axis diameter without mounting sleeve: 6 mm, mounting sleeve diameter: 8.8 mm, Keystone buttons, nickel finish