Carbon fiber tanks are high pressure SCBA cylinders that offer more usable air at higher pressures than standard steel SCUBA cylinders. They are used in air gunning, paintball, fire fighting, wind turbine maintenance, and various medical fields. The tanks are made out of composite materials developed by NASA for use in space exploration. The aluminum bladder is wrapped in carbon fiber, fiber glass, and a hard epoxy resin. This "space age" technology makes the tanks lightweight, strong and capable of accepting charging pressures of over 4500 psi. According to DOT standards they are required to be hydrostatically tested every five years and have a 15 year lifespan.