Features: 1)Suitable for frequency of 50/60Hz, rated insulation voltage up to 660V, rated operation current 620A under AC-3 duty. 2)Mainly used for making/breaking electric circuits at a long distance and for frequent starting/stopping and controlling AC motors. 3)Used in combination with thermal relays to compose a magnetic motor starter. 4)Complying with such standards as IEC60947-4-1, GB14048.4.