Carbon fiber, Bisphenol A & B, and a catalyst wet the carbon fiber with the resin, and wrap it around a cylinder I've made thousands of Hydrogen storage tanks at my job, they operate in the 10,000 psi range, I could tell you what they burst at, but it may be a trade secret let's just say it's high enough that you won't have to worry, your valves and o-rings will fail before the tank itself production is not an issue, we can ramp up to do thousands of these easily enough, the process for building these has been streamlined and made ready for mass production, our only issue is we need someone to utilize them....instead of wasting their time with this fuel cell jibjab