The Schneider Electric Preventa XCS Key Operated Safety Switch has an adjustable turret head and a plastic body When wired as recommended in relevant standards, it conforms to category 4, performance level PL e, SIL 3 and complies /ISO 13849-1, EN/IEC 61508. It simply ensures a "door-open machine stop" control on your machine, with maximal reliability. Its IP67 degree of protection makes it ideal for heavy duty use in harsh conditions