Siemens 3SE5122-0PC02 Enclosure width 56 mm. Siemens 3SE5122-0PC02 is the exact printed commercial reference for a limit or safety switch in the SIRIUS 3SE range. Siemens' official product description is: Position switch, 3SE5122 Metal enclosure 56 mm wide 3x (M20x 1.5) 2 NO/1 NC slow-action contacts with rounded plunger, stainless steel and with 3 mm overtravel.