Compression fitting

Compression fittings are mainly used on copper pipe, they are very simle in the way they work. An olive, a small ring of bras not unlike in appearence to a wedding ring, fits over the copper pipe. Then when the fitting around it is tightened they will deform the olive so it grips the pipe. Compression fittings are usually stronger than solder fittings by a small margin but are harder to airtight and dont look as nice.

Here is a cannon which uses compression fittings: Behemoth