These complete units are popular versions of the SIRIUS 3SE5 limit switches. The standard design and function of the limit switches not only make it easy to select the right switch but also enable quick and easy installation, wiring and maintenance. The SIRIUS 3SE5 is designed for safety applications up to Category 4 according to ISO 13849-1 (EN 954-1) when you select the right product and use them properly in conjunction with fail-safe evaluation units such as the 3TK28, ASISafe, SIMATIC or SINUMERIK.