this is what the unit pack for the Haz-Suit looks like from behind. as you can see, it has a radio for communication and a highly advanced filtration system design to purify the toxic and hazardous air. the packs can hold many things, as well as spare oxygen masks for those that needed them.

note that the Haz-Suit primary color is grey, but Haz-Units have been known to color their armor to easily identify from other units.