That type of pressure bottle. but for something that's seeing external pressure all of the advantages of composite materials go away and all the disadvantages come into play. so if you're using a uniform material like steel or titanium or ceramic or acrylic, you can do computer modeling with a high degree of accuracy and confidence. the second you start doing carbon composite or any kind of composite materials you're introducing two materials that are in contact with each other. the filament itself and then the epoxy matrix that it sits within. and at that point you have degradation failure. s...