Tuning keys - Sperzel locking keys 6-in-line

Set of six Sperzel Locking Keys, 6-in-line, 12:1 ratio, includes bushings and washers. String posts have staggered heights . Single pin mount, no mounting screws needed. For 9/16" - 11/16" thick headstocks, requires 10mm (13/32")-diameter holes.