This set of 6 in line left handed locking Gotoh SD91 tuners are in the traditional Kluson design used on vintage Fender guitars (and used by and sold under the Fender name for their re-issue guitars). To preserve the vintage look of the tuners we opted for Gotoh's Magnum Locking system without the thumbscrew operation, instead these use locking caps on the tuner posts, simply thread the string through the tuner post hole and begin winding, the locking cap will automatically engage at the correct tension locking the string in place, you can then bring the string up to tension as normal (to release simply detune the string until the cap releases, or if the string is broken insert a coin in the locking cap slot and release it from the string). The press fit bushing fits a 11/32" hole (8.8 mm) in the headstock to secure the string post and they also come with a 9.2 mm diameter bushing to fit slightly wider headstock post holes.