Siemens 3SE5122-0KA00 Enclosure width 56 mm. Siemens 3SE5122-0KA00 is the exact printed commercial reference for a limit or safety switch in the SIRIUS 3SE range. Siemens' official product description is: Basic switch for position switch 3SE51 Metal enclosure 56 mm according to EN 50041 Device connection 3 x (M20 x 1.5) 1 NO/2 NC slow-action contacts without actuator head.