The refill is conveniently stored in the handle where it will not be misplaced. Two long-lasting glass fiber cartridges come with every Prep Pen. Refills are available. Prep Pen's powerful glass fibers thoroughly clean every corner, crevice and pocket. Any rust, wax and dirt is removed.
Sandpaper can be too rigid to directly contact and clean the contours of a chip.
Conventional sanding only hits the high spots. Prep Pen's glass fibers get into the smallest recesses.