Quick change discs have various styles , r-locks, s-locks, and p-locks. The r-lock button is more preferred in the industry. The first step before working on any application is to put on the proper protective equipment. You will need safety goggles, gloves, and an apron to prevent any injury. Once prepared, the next part of the process is to get your die grinder ready to use. You must always make sure that the RPM of the tool does not exceed the speed of the holder, or serious injuries could happen. Twist the quick-change disc onto the holder and connect the holder to the tool and twist until tight.