The OTC 4603 is designed to remove and install frost plugs used in liquid-cooled gas and diesel engines found in automobiles, trucks, SUVs, agricultural equipment, and construction equipment. Simply use a hammer with the driver and appropriate disc to install frost plugs ranging from 1" to 2-3/8" in diameter. Set contains: OTC 4603-1 Installer Handle (18" lg.); OTC 4604-2 Frost Plug Remover; OTC 4604-3 Frost Plug Disc Set (7 ea. plus 1 retaining nut).