Our NEW Carbon Fiber Cylinders manufactured by Cobham Mission Systems (formally doing business as Carleton) are built around DOT specifications and have a working pressure of 2216 and 4500 psig. These cylinders are lightweight, composite cylinders consisting of an aluminum alloy inner shell, with a total over wrap of carbon fiber, fiberglass and an epoxy resin. They are rated for 30 minutes in duration for low pressure and 30, 45 & 60 minutes in duration for high pressure. Your choice of valve assembly. These cylinders are manufactured to the same specifications and standards as our leading new SCBA competitors.