Creates a tight fit quickly and easily and features evenly-spaced pressure points to clamp box joint fingers at the corners for maximum tightness. Cauls only apply pressure on the fingers that need it. Slots on the outside of the cauls are made to hold pennies in place to firmly support band clamps at varying heights and can be used with Rockler 25mm (1) x 4.5m (15) Band Clamp (sold separately). Creates a tight fit quickly and easily and features evenly-spaced pressure points to clamp box joint fingers at the corners for maximum tightness. Cauls only apply pressure on the fingers that need it. Slots on the outside of the cauls are made to hold pennies in place to firmly support band clamps at varying heights and can be used with Rockler 25mm (1) x 4.5m (15) Band Clamp (sold separately).