The ODST battle dress uniform (BDU) is a suit of combat armor worn by the Orbital Drop Shock Troopers, special forces of the UNSC Marine Corps. With multiple models having seen production, the suit can be configured for a variety of combat roles and can even be used in conjunction with MJOLNIR powered armor .

Concept art of the base Army BDU with minimal armor. Concept art of an Army trooper (left) and a military policeman (right). Concepts for several variants of the Army BDU.

Battle Dress Uniform (BDU) is a broad term describing any of several standard-issue combat uniforms worn by members of the UNSC Marine Corps.

There is also a non-Mjolnir version of the Recon variant used by ONI, the ODST S-1/ONI Recon BDU. Development history . A prototype was created prior to the Fall of Reach concurrently with the Mark VI Prototype. Like the Mark VI Prototype, the armor underwent field tests to …

The ODST helmet has been uncovered in the Reach beta files, but also, as of the last weekly update, we see a Spartan wearing ODST shoulder pads. Perhaps in Reach we will be able to use essentially all the ODST BDU armor pieces.

As well, the photoreactive plating technology has seen limited but successful use in several special operations ODST units. Versions Mark I . The Mark I was an experimental iteration of the SPI system used by the Spartan-IIIs of Alpha Company. The featured photoreactive panels gave the Spartans of Alpha Company a rough equivalent to active ...

The Orbital Drop Shock Troopers (ODST), informally referred to as Helljumpers, are an elite special operations component of the UNSC Marine Corps and the Corps' rapid reaction force specialized in transorbital support interdiction tactics.

Main article: ODST armor. As a variant of the standard armor worn by the Orbital Drop Shock Troopers, the UA/PPE variant shares many similarities. This version of the battle armor is specifically designed to aid an ODST in CQB-type combat conditions.

Nightfall armor is a hostile environment variant of the ODST armor developed by Cascade Stronghold Technology. A variant of the armor designed for the MJOLNIR [GEN2] platform is available for use by Spartans.

According to the Bungie writeup on the back of the Halo 2 Joyride ODST figure, the Helljumpers are from "NSWG2-ODST Team 5". That would be Team 5 of Naval Special Warfare Group 2. (This is the same writeup that gave us the first usage of SOEIV.)