MIL-DTL-38999 Series I connectors offer robust performance with up to 128 contacts in an insert, ensuring reliable connectivity in harsh environments. These circular connectors, featuring front wall mount, rear wall mount, and jam nut receptacles, are designed for military and aerospace applications. With an operating temperature range of -65 °C to 200 °C, they provide durability in extreme conditions. The connectors come in 9 shell sizes and 52 insert arrangements, accommodating various contact types including M39029 rear release crimp contacts. Constructed with high-strength aluminum shells and available in different plating options such as electroless nickel and cadmium finishes, they meet stringent industry standards. RoHS compliant versions are also offered, making them suitable for environmentally conscious projects. With their Bayonet coupling and gold-plated contacts, these connectors ensure secure and efficient electrical connections, with a service life of 500 cycles. Designed for environment-resistant wall and jam nut mounting, they are ideal for demanding applications where reliability is paramount.