This 18" (approx.) sleeve is designed for use with poured concrete. Simple put the sleeve in place and pour around for a perfectly formed opening to run pipe. Wall sleeves like this HDPE plastic sleeve are used to create an opening without having to cut into the wall. This Century-Line sleeve is made to prevent water migration. Use with Link-Seals for optimum results. Model: CS-18, Material: HDPE, ID (in.): 17.45, ID (mm.): 443.2, lbs: 15.5, Kg: 7.03