Assortment - Brass Fitting 1/4" Pipe 79pcs in PB24Sold in sets of 1 Brass pipe fittings are used to join two pieces together while providing space for an object such as a screw or bolt1. They come in various shapes and thread sizes and can join, modify, and control any liquid or gas in pipes2. Brass fittings are made with a mixture of metal alloys, mostly copper and zinc, as well as small amounts of lead, tin, manganese, nickel, aluminum or iron.