The 121566-0211 is a circular box mounting receptacle connector featuring 16 solder pin contacts (size 16) with a shell size 20 and 20-16 contact arrangement. The connector is constructed with an aluminium alloy shell plated with olive drab chromate over cadmium, polychloroprene insulator and grommet material, and copper alloy contacts with gold plating. It operates over a temperature range of -55°C to +125°C and supports a contact rating of 13.0 A at AWG16, with an insulation resistance of =5000 MO and test voltage of 2300 Vrms. The connector meets IP67 protection standards (0.2 bar pressure over 48 hours), demonstrates 500 hours salt spray resistance, and is rated for a minimum of 500 mating cycles with vibration tolerance of 200 m/s² at 10 to 2000 Hz. This connector is ideal for military, aerospace, and harsh industrial environments requiring reliable, sealed electrical connections with high durability and environmental protection.