Ballistic assault vest
From Halopedia, the Halo wiki
Template:Ratings A ballistic assault vest is a type of body armor system used by UNSC Soldiers and UNSC Marine Corps. They are worn over the wearer's camouflage utility uniform, and are made of hard black nylon.[1]
The vest itself is modular, allowing for ammunition magazines, drop pouches, canteens, etc. to be added to it for mission requirements.[2] It also features a holster for a sidearm.[3]
SSgt Avery Johnson and SSgt Nolan Byrne used ballistic assault vests throughout the duration of the First Battle of Harvest, though they are not effective against plasma weaponry.[2][3] This is because ballistic gear is designed for defense against projectile weapons, such as the ones used by the UNSC.