Series Five Lightweight Military Circular Connectors

The MIL-DTL-38999 series of connectors was born in the 1960’s to provide a ruggedized military solution featuring smaller contacts and higher density insert patterns than the already popular MIL-DTL-5015. In the decades since, D38999 connectors have increased in popularity and have become the standard in Mil-Spec connectors for military and aerospace applications.

Along the way, continuous evolution has brought about new shell styles, new coupling methods, new derivatives, and new capabilities, all while remaining as popular as ever.  Amphenol’s new Series Five connector is the next evolutionary step in that impressive lineage, combining all of the capabilities of the traditional 38999 style connector in a lighter, smaller, and more compact package to support the aerospace industry’s ever-changing demands.

FAQs: Series Five Connectors

How is the Series Five Connector different from MIL-DTL-38999 Series III?

The Series Five Connector retains all the rugged capabilities of MIL-DTL-38999 but in a more compact, lightweight design:

• 20% smaller (reduced footprint for high-density applications)
• Up to 50% lighter (ideal for weight-sensitive military and aerospace platforms)
• Higher voltage capabilities (improved performance in harsh environments)

What applications benefit most from Series Five’s lightweight design?

Key use cases include:

• UAVs & Drones (weight-critical missions)
• Satellites & Spacecraft (launch payload optimization)
• Portable Defense Systems (easier transport/maneuverability)

Where can I get detailed specifications for Series Five?

Download the Series Five Catalog for:

• Dimensional drawings
• Weight comparisons vs. Series III
• Electrical/mechanical performance data

• 38999-Qualified Insulator and EMI Spring
• No Dielectric Bond Joint
• Triple Wire Seal
• AS39029-Qualified Gold-Plated Contacts
• Full Metal Clip Contact Retention
• Standard Accessory Thread
• Radial Interfacial Seal
• "Diamond-Grip" Nut Design
• Scoop Proof
• No-Mess Dry Film Thread Lubricant
• Optimized Ratcheting Torque
• "No-Slop" Tolerance Interface
• Quick Coupling Double Start Thread

What is the Diamond Grip coupling nut in Series Five Connectors?

The Diamond Grip coupling nut features advanced quick-coupling with:

• Textured nut design – Improves grip, even with gloves or in wet conditions
• Double-start thread – Faster mating/unmating than standard threads.
• Textured nut design – Improves grip, even with gloves or in wet conditions.
• Full-metal retention clip – Ensures a secure, dielectric-free connection for enhanced reliability.

▶ Watch it in action: Series Five Connectors Video

How does Series Five’s lightweight design save fuel costs?

For every pound an airline saves, it equates to roughly 14,000 gallons of fuel savings per year.” Reducing weight and space in aerospace applications allows room for other devices and saves millions of dollars on aircraft.