Previously known as MIL-C-38999, MIL-DTL-38999 connectors come in four series: Series I, Series II, Series III and Series IV. They are environmentally resistant connectors that use removable crimp contacts and have an operating range of -65 to +200°C.

Series I connectors are bayonet coupled and have high-vibration properties. They are scoop proof and are ideal for heavy wind and moisture environments. They are utilised when a fast disconnect coupling system is required.

Series II connectors are bayonet coupled, are non-scoop proof, and have a low profile, so are used when weight or space is limited, or in low-vibration, high moisture, and strong wind situations.

Series III connectors are coupled by a quick screw Tri start thread, are scoop proof, and are best suited for normal mating and unmating applications and can be used in high temperature, moisture, wind, or vibration environments when used with the correct accessories. Series III connectors are most commonly use in Military and Aerospace designs.

Series IV connectors are coupled by a Breech-Lok mechanism, are scoop proof, lightweight and suitable for blind mating applications, and they also have high-vibration attributes. They are well suited in high wind and moisture environments when used with the appropriate accessories.

MIL-DTL-38999 Specifications and Datasheets

The most recent MIL-DTL-38999 specification can be downloaded from Defense Logistics Agency Land and Maritime website: click here to download.

Major manufactures of D38999 connectors include Amphenol, TE Connectivity, Glenair, Souriau, Conesys, ITT Cannon and Eaton. You can download each manufacturer’s datasheets using links in the following table.

Manufacturer	Datasheet
	Series I	Series II	Series III	Series IV
Amphenol
Conesys
Eaton
Glenair
ITT-Cannon
Souriau
TE Deutsch