CAT 25 Stairwell - The CAT25 includes the fiberglass toroidal structure, fiberglass entranceway, fiberglass/composite hatch, MCAS air filtration system for nuclear-biological-chemical environments, septic system, fiberglass water tank, fiberglass flooring, fiberglass counter, fiberglass shower walls, fiberglass battery housings, two toilets, Forty 12- volt deep cycle batteries, air blower, gray water tanks, all wiring, and all plumbing, etc.