Locking tuners have the advantage that you need very little spare string as they are gripped by the screw-in locking mechanism and that means that there's much less string wrapped around the capstan which helps the guitar stay in tune, especially through changes in temperature.I fitted these to my Ibanez Gio Strat style guitar with 10mm holes. They fitted exactly, no drilling new or larger holes was needed. In the first 2 pictures, I've only fitted 1 new machine head on the low E string position so you can see that the capstan sticks out a lot less than the stock ones but the angle the string takes from the nut to the capstan is still the same. In the last picture, all 6 have been fitted.I've used Musiclily products before and have always been happy with the quality, these locking machine heads fully met up to my expectations. The tuning action is firm but not stiff and the locking mechanism grips the strings firmly as expected. Fitting them was really easy; it really doesn't take much more than 5 minutes added to the time to do a string change.For the price, these are a bargain and I highly recommend them.