The SMC series which is introduced Limitorque technology from USA is a kind of muti-turn valve electric actuator. It has been widely used to petroleum, chemical engineering ,metallurgy, electric power ,military ,municipal ,light industry ,food and other fields. It is possible to control a machine locally or remotely. This series has a lot of type specifications such as general type, explosion-proof type, integrated type, integrated explosion-proof  and so on.