MIL-DTL-38999 Series II connectors are designed for harsh environments, offering up to 128 contacts in a single insert. These connectors are environmentally sealed and can operate in temperatures ranging from -65 °C to 200 °C. Featuring various mounting options such as front wall, rear wall, jam nut, and box mount receptacles, they provide flexibility for different applications. Available in 9 shell sizes and 52 insert arrangements, they use M39029 rear release crimp contacts in sizes 22D, 22M, 22, 20, 16, and 12. Constructed with aluminum shells and offering multiple plating options including cadmium-free finishes, these connectors ensure reliability and durability. The MS27499 designation signifies their compliance with military specification MIL-DTL-38999 II, making them suitable for demanding military and aerospace environments. Whether for box mounting, through bulkhead installation, or other applications, these connectors with gold-plated contacts and electroless nickel or cadmium olive drab finishes are ideal for ensuring secure electrical connections in challenging conditions.