MIL-DTL-38999 Series II connectors, featuring up to 128 contacts in an insert, are designed for harsh environments with an operating temperature range of -65 °C to 200 °C. These environmentally sealed connectors come in various mounting options such as front and rear wall mount, jam nut, and box mount receptacles. Available in 9 shell sizes and 52 insert arrangements, they use M39029 rear release crimp contacts for reliable connections. The connectors, with aluminum shells and multiple plating options including cadmium-free finishes, ensure durability and conductivity. Ideal for military and aerospace applications, they offer secure mating with bayonet coupling and feature RoHS compliance for environmental sustainability.