CONNECTOR CIRC 21-75 4WAY SIZE 21; Military Specification:MIL-DTL-38999 Series III; Circular Connector Shell Style:Straight Plug; No. of Contacts:4Contacts; Circular Contact Type:Crimp Pin; Coupling Style:Threaded; Insert Arrangement:21-75; Connector Body Material:Aluminium Alloy Body; Connector Body Plating:Olive Drab Chromate over Cadmium; Contact Material:Copper Alloy; Contact Plating:Gold; Insert Rotation:B; Service Class:Corrosion Resistant EMI; Product Range:MIL-DTL-38999 Series III