This Schneider Electric Harmony XB4 Emergency stop 40mm mushroom red button head operates with a latched turn-to-release mechanism. It has a chromium-plated metal bezel. This emergency stop / shutdown button head is easily combined with contact blocks and installed into standard 22 mm 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 proof, waterproof and vibration resistant thanks to its IP66 / IP67 / IP69 / IP69K, making it ideal for operation in harsh environments.