Attesting to the fact that NSK has established itself in the handpiece industry is the availability of replacement parts. NSK Back Caps are now available for most models. Of course, NSK Back Caps should be replaced when obviously broken, but they should also be periodically replaced to ensure the best turbine performance, and prevent early turbine failure due to increased back pressure and rubbing. If NSK Back Cap button sticks in, it will rub the chuck actuator button causing excess heat and eventual turbine failure. An indicator of this problem would be button feeling warm when removing the bur.