MIL-DTL-38999 Connectors are Ready for the Harshest Environments

MIL-DTL-38999 connectors are miniature, high-density circular connectors made for some of the most demanding conditions and harshest environments imaginable. These electrical connectors have been intentionally designed to meet very strict Mil-Spec requirements set forth by the U.S. Department of Defense to establish an industry standard for performance and reliability. Despite being designed for the military, 38999 connectors now can be found in a wide variety of applications including commercial aerospace, industrial, marine, communication, entertainment, medical, and even automotive commercial applications.

MIL-DTL-38999 Series

MIL-DTL-38999 connectors encompass four different series. Series I connectors have a bayonet coupling mechanism and are designed to be scoop-proof and perform well in environments with moisture, wind, and high vibration. Series II connectors are also bayonet connectors to include a low-profile design to accommodate weight and/or space restrictions. This variation of 38999 connector is not scoop-proof, but will still function well in environments with wind, moisture, and low vibration.

D38999 Series III connectors differ from Series I and II in that they use a self-locking threaded coupling system. They are scoop-proof and perform well in high-temperature environments that may include vibration, moisture, or wind. There are also Series IV connectors that use a Breech-Lock mechanism for coupling. Like the Series III design, they are scoop-proof and do well in high-vibration environments. These connectors are perfect for blind mating applications and only require 90-degree rotation to engage and disengage.

Let’s take a look at the first three MIL-DTL-38999 series from a few of the industry-leading manufacturers.

SOURIAU 38999 Series I

SOURIAU MIL-DTL-38999 Series I Connectors (8LT Series)

One well-known manufacturer of 38999 Series I connectors is Souriau. The D38999 Series I connector is a circular, high-density bayonet style with shell sizes ranging from 9 to 25 with over 50 QPL approved insert arrangements available. It was designed for high-performance requirements for military and aerospace cable to panel applications. Other applications can include marine and communication equipment, medical instrumentation, weapon systems, armored carriers and tanks and test equipment.

These subminiature circular connectors are ideal for use in tight spaces requiring protection against extremely harsh environmental conditions. The connectors use a bayonet coupling mechanism and are scoop-proof to protect contact integrity. A scoop-proof design prevents the possibility of bending or shorting contacts during the mating and unmating process by having the pins recessed back in an elongated shell.


CORSAIR 38999 Series II

Corsair MIL-DTL 38999 II (MS274** Series)

Corsair MIL-DTL-38999 series II connectors are used in performance military and civil aviation applications that demand reliable connections in some of the harshest environments. MIL-DTL-38999 Series II connectors have to deliver exceptional performance under wide temperature ranges, high vibrations, and be resistant to a vast array of pollutants. Corsair’s version of the series II is a match to all the Souriau and Amphenol JT series connectors.

Air Electro stocks all the mil prefix numbers for your MIL-DTL-38999 Series II connectors including:

MS27472, MS27473, MS27474, MS27484, MS27497, MS27499, MS27500, MS27508 and MS27513.

As a value added, stocking distributor for Corsair, Air Electro is a premier source for MIL-DTL-38999 Series II connectors, with a 48-hour value added turnaround time as well as ample stock on the full breadth of shell types, sizes, plating options and insert arrangements.


TE Connectivity Deutsch hermetic MIL-DTL-38999 series III (EN3645) provide a superior performance where most robust connectors fail. Air Electro stocks a large amount of MIL-DTL-38999 I and III and can assist in a variety of desired applications. Hermetic termination styles include solder cups, eyelets, PC tails, weld tabs and crimp termination. These connectors are used for high performance applications and are glass-to-metal sealing used for harsh environments.


    • Modified flanges
    • Any termination style
    • Special materials (such as titanium)
    • High-temperature and cryogenic materials
    • Ability to withstand high pressure

Air Electro Inc: Your Partner for MIL-DTL-38999 Connector Solutions

In order to specify the correct electrical connector for your application, knowing the differences between the various Mil-Spec 38999 connector series is critical. Whether your application calls for a low-profile connector that can withstand low vibration conditions or one that must combat high temperatures and moisture, having a partner that will advise you on the best solution is important, especially when it comes to meeting the Military Standard requirements. Additional to the manufacturers discussed above, MIL-DTL-38999 connectors are also available from other industry-leading manufacturers such as Glenair. No matter the situation, Air Electro can assist you in specifying a standard 38999 connector or even custom assemble one to meet any application requirement.

Leave a Reply

Show Buttons
Hide Buttons