U.S. Plastic Corp.® has a large selection of PVC pipe fittings which are polymerized vinyl chloride, a synthetic resin, which when plasticized or softened with other chemicals has some rubber-like properties. Derived from acetylene and anhydrous hydrochloric acid. Our PVC pipe fittings have nominal sizes (1/4, 3/8, 1/2, ect. although they are not these exact sizes) that are socket fittings (schedule 40) and socket or threaded fittings (schedule 80). All socket fittings are designed to go on the outside of the pipe, not the inside. We carry a wide variety of fittings that many times come in both white and gray.