This Harmony XB5 emergency stop / shutdown 30mm mushroom button red button head operates with a locked key release mechanism (key #455). It has a plastic bezel. 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 mounts easily onto compatible complete emergency stop and shutdown buttons. A clear color and distinctive 30mm mushroom shape make it visually easy to spot from a distance. Thanks to its IP66 protection rating, it is shockproof, dustproof, waterproof and vibration resistant, making it ideal for use in harsh environments.