This Harmony XB4, blue button head operates with a spring return mechanism. This button head provides an ergonomic interface for controlling your machines. It is easily installed and replaced on compatible complete push button units and contact blocks via snap-fit assembly. It is impact resistant, dust resistant, water resistant and vibration resistant thanks to its IP66 / IP67 / IP69 / IP69K. 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.