Differences Between D38999 Series I, II, and III Connectors

The D38999 series connectors are a sturdy, dependable family of military-grade connectors designed for aerospace, defense, and rugged industrial tasks. They come in three versions—Series I, Series II, and Series III—each tailored to different needs. At their core, they all keep connections secure in tough conditions, but they vary in build, sealing, and where they perform best.

D38999 Series I: The Everyday Workhorse

Take Series I connectors, for instance. They’re a popular pick for military and aerospace folks who need something reliable without a big price tag. With a threaded coupling setup, they lock together firmly—simple to use and hard to jostle loose.

Shell Material and Finish: Made from lightweight aluminum alloy with a standard corrosion-resistant coating, they hold up well in moderately challenging spots.

Size and Configuration: They come in a wide range of sizes and layouts, so they work for all kinds of setups.

Standout Features: The threaded design makes connecting them a breeze, and their sealing does a decent job keeping out moisture, dust, and light wear.

Series I is great for routine jobs where you need solid performance but aren’t facing extreme conditions. Think indoor command systems or basic communication gear that doesn’t have to endure a storm or battlefield.etc.

D38999 Series II: Stepping It Up

Series II builds on that foundation. It’s like a sturdier version of Series I—same general shape and threaded coupling, but with improved protection for trickier settings.

Shell Material and Finish: Still aluminum alloy, but with a better finish—options like cadmium or other coatings that handle corrosion well, even in harsher spots.

Size and Configuration: Sizing is close to Series I, though you get extra choices for mounting and wiring.

Standout Features: The sealing is stronger here, offering better defense against dust, water, and some chemicals, which makes it a good fit for tougher environments.

Series II works well when you need more durability—like in military vehicles or avionics—where dust, vibrations, and moderate weather are factors.

D38999 Series III: Built for the Extreme

Then there’s Series III, the top dog of the D38999 lineup. These are crafted for the harshest, most demanding conditions—think gear that absolutely can’t fail.

Shell Material and Finish: Instead of aluminum, Series III uses stainless steel. That gives it excellent strength, strong corrosion resistance, and the ability to handle extreme heat, cold, or chemicals.

Size and Configuration: Same size range as the others, but built tougher to withstand serious stress.

Standout Features: The sealing is exceptional—keeping out heavy moisture, dust, big temperature shifts, and strong vibrations. These meet the toughest military and aerospace standards.

You’ll find Series III in intense applications like space missions, fighter jets, or submarines—places where connectors face brutal conditions and still need to perform flawlessly.

Wrapping It Up

So, that’s the rundown on the D38999 family: Series I, II, and III. Series I is your budget-friendly, all-around option for standard tasks. Series II boosts the protection for tougher-but-manageable conditions. And Series III is the heavy-duty choice for the most extreme environments, where reliability is non-negotiable.

Choosing one depends on what you’re dealing with—how harsh the setting is and what performance you need. Whether it’s an affordable solution for milder jobs, a dependable pick for moderate challenges, or a robust connector for the roughest duties, there’s a D38999 that fits.