The switch has the following functions, derived from power outage and undervoltage protection. Bipolar cut-off, unipolar cut-off functionBoth versions can be combined with overload protection switches for undervoltage and overload protectionWidely used in machine tools, power tools, garden machinery and above. This is a safety switch. After the device is accidentally powered off, it will not turn on. You need to press the green start button to turn it on.Type: AC220V KJD17 4 Pincolor:BlackMaterial:plasticPackage Contents:1 x electromagnetic push button switchOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.