From Halopedia, the Halo wiki
The COMM variant of ODST armor bears resemblance to the late war design of the armor, with a notably more angular design. It comes equipped with a communications backpack containing a battle network relay capable of providing the user with a multi-channel secure network uplink. The case meets or exceeds all UNSC mil-spec standards for temperature, impact, moisture, vibration, and foreign particulate resistance. The armor's component pieces are capable of being employed on the Mark VI MJOLNIR platform. The ODST/COMM armor is rated for vacuum, allowing operators to perform short spacewalks on the exterior of spacecraft when needed.
Halo: Fireteam Raven
The ODST/COMM armor is worn by players playing as Marcus Hudson. It confers no in-game effects.
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