The PDR sliding hammer is used in connection with glue and pull knobs for paintless dent removal. The weight has a square cross section, preventing the hammer from rolling off any car. The weight itself is covered in plastic, which prevents it from scratching any painted parts it might be lain down on. Our green glue was developped specifically for use with the sliding hammer. For best results use knobs over 20mm in diameter with our green glue, without letting the glue cool off completely.