Schaller M6 135° Locking 6 In Line Staggered Tuners
Schaller M6L Locking Machine Heads - 6 In Line, Staggered, 135° Screw Position
The Schaller M6L comes with a locking mechanism to lock the string in place rather than winding around the post. The string is threaded as usual through the eye of post and then, using the thumbwheel on the back of the tuner body, the pin is tightened against the string. You would then tune the guitar up as usual. Changing strings is quick and easy!
The locking mechanism also improves your guitar's tuning stability. Guitar strings tend to slip when wound around the post, often after aggressive playing or bending - having a locking mechanism completely removes this problem.