XB2 high ratio dual - B) series button is suitable for use in ac 50 hz - 60 hz, rated voltage 380 v and 220 v dc working voltage Scope of application: LA137 - B (XB2 high ratio dual - B) series button is suitable for use in ac 50 hz - 60 hz, rated voltage 380 v and 220 v dc working voltage of industrial control circuit, as magnetic starter, contactors, relays, and other electrical appliances line ...