IEC 61076-2-106:2011 describes circular connectors with IP40 or IP65/67 protection degree, typically used for industrial process measurement and control. These connectors consist of fixed and free connectors, either rewireable or non-rewireable, with M16 x 0,75 screw-locking. Male connectors have round contacts Ø 1,5 mm or Ø 1,0 mm.