For use on wood doors. Features pneumatic design to cushion shock and absorb noise. Insert into 1/4" hole in door frame. Height: 3/4" Diameter: 3/8" Thickness: 1/8". To prevent removal a small brad should be driven into stop strip and through stem of silencer. Additional Details ------------------------------ Product description: For use on wood doors. Features pneumatic design to cushion shock and absorb noise. Insert into 1/4" hole in door frame. Height: 3/4" Diameter: 3/8" Thickness: 1/8". To prevent removal a small brad should be driven into stop strip and through stem of silencer.