Siemens 3SE5122-3KA00 Enclosure width 56 mm. Siemens 3SE5122-3KA00 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 wide Device connection 3x (M20x 1.5) 1 NO/2 NC slow-action contacts with 2 LEDs, yellow/green 110-230 V AC without actuator head.