MIL-DTL-38999 Series I connectors feature up to 128 contacts in an environmentally sealed insert, designed for harsh environments with an operating temperature range of -65 °C to 200 °C. Available in various configurations including front and rear wall mount receptacles, as well as jam nut receptacles, they offer RFI grounding options. With 9 shell sizes and 52 insert arrangements, these connectors utilize M39029 rear release crimp contacts, catering to sizes 22D, 22M, 22, 20, 16, and 8 for coax and twinax applications. Constructed with high-strength aluminum shells, they come in plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, with RoHS compliant finishes. The MS27505 connectors, part of the 38999 Series I military specification, are designed for box mounting with a back panel flange, featuring bayonet coupling for secure connections in demanding environments.