Pipes and threads and valves and hoses and BSP and NTF and inch and millimeter ...

The membrane is within a tube (called high pressure vessel), the vessel has 3 openings with threads to screw fittings into. Then you need a high-pressure needle valve to adjust the pressure, a relieve valve for security reasons, 3-way-valves, hose connectors, bows, filters with connectors and threads, and and and. All of them should be seawater resistant.

When I looked for them in the internet I found items for 10 USD and for 100 USD doing the same thing. I wanted to understand the differences (which turned out to be a time consuming and anyway useless hobby. Some parts are the same but without a stamp that says: "medical proof" or "may be used in nuclear power plants" whereas others are intended to be used in agricultural machines or pressure washers). Putting together the most reasonable parts turned out to drive me mad: one part had a 1/4" NPT thread and should be connected to a 1/4" BSP thread. Then there is a 1/4" NPTF that should fit onto 10 mm. some of them are self-sealing, some of them need a sealant, some of them for hydraulics, others for gas, others for marmalade or so.

One inch equals 25.4 mm, but if you measure a 1" pipe you find that it is 25.4 mm neither inside nor outside. Same is true for 1/4 inch, 1/2 inch, or 3/4 inch. You may measure any way, you will never find one inch when you measure a 1" pipe or hose or thread. I felt confused to a certain extent.

I studied anthropology at university not any technical sciences, and I suddenly understood why the NASA once lost a space probe on Mars due to the fact that in a computer landing software they mixed up meter and feet. Thus, I thought, if this happens to NASA engineers why should I do better. So, I ordered many parts at least twice. My workshop is full of brand new parts now that might make a small rocket or at least a chemical laboratory.

But finally, the foot bone was connected to the ankle bone, the ankle bone connected to the shinbone, the shinbone connected to the knee bone and them bones walked.