MS3102A18-4S is a MIL-DTL-5015 Type standard cylindrical box mounting receptacle connector designed for military and aerospace applications requiring reliable electrical connections. The connector features an 18-size shell with a 4-contact insert arrangement, constructed from high-grade aluminum alloy with electrically conductive cadmium plate finish and olive drab chromate after-treat for superior corrosion resistance. Contacts are available in both solder and crimp versions, machined from copper alloy with silver plated finish for maximum corrosion resistance and low millivolt drop. The resilient neoprene inserts provide high dielectric strength, high arc resistance, and resistance to vibration, with the capability to pressurize either pin or socket insert. This connector is widely used in military equipment, aerospace systems, and other demanding environments where environmental sealing, durability, and reliable signal transmission are critical requirements.