In a PC, fittings are what hold all your tubes together and connect water blocks to pumps and radiators. It’s not enough to simply attach a soft or hard tube to a block and call it a day. You need to add a fitting to create a water-tight seal. When working with electronics and liquids, you need to be double (and triple) certain no leaks will occur. There are a number of fitting types available, as well as sizing and materials. Much like other parts of a water-cooling loop inside a PC, choosing fittings for your system is a simple process. But you need to bear in mind the materials used to make said fittings. It’s not recommended to mix material types. If you have a copper radiator and water block but nickel fittings, you’ll be fine. Copper and nickel are usually OK to use together, but when you throw aluminum or silver into the mix, things can get messy with galvanic corrosion. The second consideration is size, which needs to match your tubing. Both tubing and fittings can be purchased at the following sizes. ID and OD stand for inner diameter and outer diameter, respectively. For soft tubing, you have two choices. The first is the barb, which simply allows the...