This Harmony XB5 40mm mushroom button blue button head operates with a locked twist to release the mechanism. It has a round shape and a protective collar. This illuminated 40mm mushroom shaped push button head for integrated LEDs 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. The illuminated head makes it visually clear from a distance. Thanks to its IP66 rating, it is shockproof, dustproof, waterproof and vibration resistant, making it ideal for use in harsh environments.