Schaller BMF Bass Tuner Set 4L BC , Machine Head Set for Electric Bass, Suitable as replacement machine heads for F-style basses, With a longer wing and a larger base plate, Style: 4 Links, Construction: Open, Gear ratio: 1:20, Shaft length: 21 mm, Bore: 17.5 mm, Attachment: Screws & sleeves, Schaller No.: 10260401.27.71, Finish: Chrome-plated black, Includes: Fixing screws and counter bearing, Made in Germany