48 cubic in., 3,000 psi HPA (High Pressure Air) nitrogen/ compressed air tank with pressure regulated hose. Used for paintball. both parts new cost ~45$ from ebay.com .This will be used for the future recharging of my shocks. A local air compressor shop quoted me $20 to fill this tank. Considering a shock is only charged to 150 - 300psi max, and has a small area for gas internally, this should last me a long time.