Bought to replace the standard tuning pegs on my Jackson JS22-7 Dinky. The installation was very easy, plug & play and the screw holes were matching 100% the tuning peg angle.
The Schaller M6 is top quality, it adds mass in your headstock and in my case improved tuning stability (in conjunction with a new black TUSQ nut). Turning the button is a real pleasure and the gear ratio improved accuracy in fine tuning.
My only complain is the price tag...both for the set or the standalone Schaller tuning peg. There are many options out there with similar quality at more affordable price.