The Bernstein SLK-F-UC-55-R1-A0-L0-4 is a safety switch featuring a bolting contact block, NC + NO circuitry, IP67 protection level, and an M20 electrical connector. It is a robust, reliable switch offering resistance to dirt, dust, water, and other environmental factors. The SLK's bolting contact block allows for easy installation and makes it suitable for indoor or outdoor use. Additionally, the SLK has a wide operating range, making it suitable for a variety of applications.