The 121073-0156 is an ITT Cannon Combo D rectangular connector receptacle designed for high-reliability interconnect applications in military, aerospace, and industrial environments. The connector features a brass shell with yellow chromate over cadmium plating per QQ-P-46 Type II Class 2, and copper alloy contacts with gold plating (50 microinches minimum thickness per MIL-G-45204 Type II Class 1) over copper per MIL-C-14550. The insulator is constructed from polycyclohexylene dimethyl terephthalate or polyphenylene sulfide co-polymer per 24308-Style, available in white or black. Multiple shell sizes (DE, DA, DB, DC, DD) accommodate various contact arrangements with Size 20 and Size 8 cavities, supporting both standard and coaxial (75 Ohm or 50 Ohm) contact options. This connector is engineered for demanding applications requiring robust electrical performance, environmental resistance, and long-term reliability in aerospace, military, and industrial instrumentation systems.