MIL-DTL-38999 Series I connectors feature up to 128 contacts in an insert, designed for harsh environments with a wide operating temperature range of -65 °C to 200 °C. Offering front wall mount, rear wall mount, and jam nut receptacles with RFI grounding plugs, they come in 9 shell sizes and 52 insert arrangements. Utilizing M39029 rear release crimp contacts in various sizes, including coax and twinax, these connectors are housed in high-strength aluminum shells with options for plating, such as cadmium-free finishes. Meeting military specification MIL-DTL-38999 I, they ensure reliable performance with gold-plated contacts, bayonet coupling, and environmental resistance, making them ideal for demanding applications. With a service rating of M and service class E, they are suitable for environment-resistant box and through bulkhead mounting receptacle types.