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. The connector family includes front wall mount, rear wall mount, and jam nut receptacles, along with RFI grounding plugs. Available in 9 shell sizes and 52 insert arrangements, they utilize M39029 rear release crimp contacts in various sizes. These connectors boast high-strength aluminum shells with plating options such as light iridescent yellow cadmium, olive drab cadmium, electroless nickel, and black anodized aluminum, some of which are RoHS certified. Suitable for military and industrial applications, they ensure reliable performance with features like bayonet coupling, gold contact plating, and a service rating of M. With a service class of T, they are ideal for environment-resistant wall and jam nut mounting receptacles and plugs, offering conductivity and durability with a mating life of 500 cycles.