This Harmony XB5 40mm mushroom button yellow button head operates with a spring return. It has a double insulated protective collar. 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 ergonomics. It combines easily with the Harmony series contact blocks to perform a variety of control functions. A distinctive 40mm mushroom shape makes it visually clear from a distance. It is shockproof, dustproof, waterproof and vibration resistant thanks to its IP66 / IP67 / IP69 / IP69K protection rating, making it ideal for use in harsh environments.