Fittings are the parts that keep your system together, from T fittings, to union elbows, to couplings, we carry them all. The important thing to know before ordering fittings is whether you need 1/4" or 3/8" fittings. The 1/4" fittings are usually the size used on the tubing runs. Commercial runs in places like ranches, or extra long runs are the types of installations where 3/8" fittings may have been used. If you are unsure, measure the inside diameter of the tubing, not the outside diameter.