This set includes 4 pieces of 3/4" x 3/4" x 1/2" Propex Poly Tee expansion fittings made of Pex A and poly alloy materials. The fittings are compatible with brands such as Wirsbo, Sioux Chief, Uponor, Propex, and all other Pex A expansion brands. The set comes with an adapter and is perfect for plumbing and fixtures, home improvement, and home & garden projects.