There are a few different types of flexible tube fittings. They are often used with faucets that use soft-copper supply tubes. These fittings can be bent into place and shaped, then attached with a coupling nut. Because they cannot be looped around, you must cut the tubing to the proper length before attaching it. In some cases, you may need to cut it longer or shorter, depending on the size of your faucet and the length of your supply line.

Faucets with compression fittings often feature a large nut on one end and a smaller nut behind it. To connect the two, you should first hold the smaller nut in place and then turn the large nut on the other end. This way, the nut will hold the flex hose securely while the two halves fit together. If they don't, you can simply remove the flex tube and attach it to the faucet.

Soft-copper supply lines are generally pre-shaped when you purchase them. Before attempting to install one, you should measure the distance between the faucet and the water supply. Some faucets have soft-copper supply lines that attach directly to shut-off valves. If you're unsure, you can pre-shape the flexible line to match the length of your supply line. This doesn't need to be exact.