Partsland J07LKJ-CR-R6 Chrome Stemmemaskiner til guitar

I must admit I didn't exactly know what locking tuners meant when I chose these, but man, have I been living under a rock... They're really good and my Squier Fat Strat has never stayed so well in-tune for so long in 18 years. One minus, but it's most likely my fault: my Strat doesn't have anti-rotation screws in this position and I had to drill the holes myself and most likely because I didn't use the proper drill head / was afraid to go too deep, I tightened them by hand and two of the screws' heads broke, leaving the rest of the screw in the wood. But let's say that tightening the nut well enough made the screws optional for me.