This Harmony XB4 emergency stop / shutdown 40mm mushroom head modular red push button operates with a latched-turn-to-release mechanism.It has a metal bezel.This emergency stop / shutdown button, also called EMS (Emergency Machine Stop) and EMO (Emergency Off), is easily installed into standard 22mm diameter cut-outs and connected with simple screw-clamp connections.It is clearly distinguishable visually at a distance thanks to a clear color and a prominent 40mm mushroom shape.It is impact resistant, dust resistant, water resistant and vibration resistant thanks to its IP66 / IP67 / IP69 / IP69K, making it ideal for operation in harsh environments.