Shell flame retardant plastic, steel core silicide W600, dynamic and static contact for copper pieces of silver, aluminum alloy base is fit for ac 50/60 hz, for long distance with the breaker circuit and frequent starting. Control of ac motor, etc., can also be assembled into modular auxiliary contact. Air delay head. Mechanical chain of latency, reversible, star delta starter, can also and hot after inserting electromagnetic starter. Flame retardant enclosure, copper pieces of silver, copper coils.