SMOOTHEN AND REINFORCE THE CALLUSES - Long duration system to maintain or get rid of the calluses. Very easy to keep and to use. SAY GOODBYE TO TRAINING WITH PAIN - Forget ripping your hands during WODs because of the excess of calluses. The correct caring of the calluses makes the difference between stopping a training because of a skin issue and not having to. REMOVABLE AND EXCHANGEABLE SANDING BAR - Once you have the handle you can exchange the sanding bar when needed. Just change them when it doesn't perform well anymore.