We use a tool to torque down the screws on the belt so they do not work loose and fall off with the vibrations of wearing the belt. Normally you can just use a flat head screwdriver to unscrew the screws and change out the buckle. If that doesn't work, wrap a piece of sticky tape around your finger (sticky out) to hold the smooth side of the screw.  Please visit this link for a helpful video on how to do this. CLICK HERE