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.