This Harmony XB4, 40mm mushroom black button head operates with a spring return / impulse mechanism. This 40mm mushroom shaped push button head is ideal for situations where quick actions are required for a process or machine to function correctly or where operator movements require maximum ergonomy. It is easily combined with Harmony range of contact blocks to perform a large variety of control functions. It is clearly distinguishable visually at a distance thanks to 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. Its wide range of operating temperatures from -40°C to 70°C allows versatility in usage of product. Its highly ergonomic mushroom push button shape makes it ideal for use in area where operator wear thick gloves or where users have impaired movements.