To replace Kavo back caps, you need the wrench included with the handpiece. If you don’t have the wrench, ask the dealer you purchase the cap from to provide one. Another good tool for removing Kavo back caps is a pair of c-ring pliers with tips small enough to fit into back cap holes. Push wrench, or plier tips, into back cap holes and twist while pushing in. This motion will align button holes with holes on interior of cap. Once holes are aligned, and wrench tips are inserted into interior holes as well, loosen cap by turning to the left. Make sure new cap has the required o-ring installed, and screw cap on by turning to the right. Replacing Kavo back caps requires a little patience the first time or two, but you can save as much as $80 by doing it yourself.