This Harmony XB4, emergency stop / shutdown 40mm mushroom red button head operates with a latched key release (key no.421E) mechanism. This emergency stop / shutdown button head also called EMS (Emergency Machine Stop) and EMO (Emergency Off) provides an ergonomic interface for controlling your machines. It is easily installed on compatible complete emergency stop and switching off pushbuttons. 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. It has a metal bezel, this makes it Ideal for applications requiring high impact and vibration resistance. It is designed to fit in a standard 22mm cutout, ensuring compatibility when installing in pre-existing machinery. Secure machine and system operation with a key, only available to authorized operators. Its wide range of operating temperatures from -40°C to 70°C allows versatility in usage of product.