Cle de Carter

A sump-plug or drain-plug wrench or key usually has a range of probably 5-10 head sizes for undoing and tightening various sizes of sump, rear axle, or gearbox drain plugs. Some wrenches have spanner-type heads for fitting over projecting plugs; others have key-type heads for fitting into recessed drain-plugs. Combination wrenches have a mixture of both types.