These are locking machine heads and are great for quick string changes and tuning stability. I ordered these for my Gibson but they did not fit. My loss is your gain. These took months to get here, they are not readily available in Canada. I paid $134.47 for these and you can get them for only $110.
Here's a link the the Schaller web page: http://guitar-parts.biz/hp530828/Original-G-Series-Keystone-SR-Toplocking-10490523.htm?ITServ=C126bc15aX1570ed882e3XYfa5