Wera hmb zyklop 38in ratchet sockets wera 05003566001 this 21mm socket from wera can be used with a zyklop ratchet with 38in square drive to tighten or loosen hexagon headed screws nuts and bolts made from chrome vanadium with a brushed chrome plated finish this socket is suitable for use with both hand and non impact power tools wera 05003566001 hmb zyklop ratchet 38in socket 21mm