MIL-DTL-38999 Series I connectors, part of the 38999 I harsh environment connector family, feature front and rear wall mount receptacles and RFI grounding plugs. With up to 128 contacts in an insert, they offer high strength aluminum shells and various plating options, including cadmium-free finishes. Operating between -65°C and 200°C, these circular connectors are designed for demanding environments, meeting military specification MIL-DTL-38999 I. Suitable for applications requiring conductivity and environmental resistance, they come in 9 shell sizes and 52 insert arrangements, accommodating M39029 rear release crimp contacts. The bayonet coupling mechanism ensures secure mating, with a service rating of M for durability. Suitable for wall and jam nut mounting, these connectors are essential for reliable electrical connections in aerospace, defense, and other industries.