How big/large is the reservoir?

The dimensions of the reservoir are 60″ length x 80″ height x 3″ depth (uninflated). When inflated, the reservoir depth increases to 24″ and the reservoir is shaped like a giant pillow. For hanging the reservoir you will need about 5 feet of open wall or ceiling space with a hanging height of a least 6-1/2 feet and 2 feet of working clearance when the reservoir is fully inflated. When fully inflated the reservoir holds over 600 liters of oxygen concentrated air at a passive pressure.