This is a Century-Line brand HDPE (polyethylene) wall sleeve used to house pipe lines in concrete. This is referred to as a 12" sleeve (see actual ID below). The light weight makes for easy installation even by one person! Corrosion and impact resistant - will stand up to industrial jobs. Model: CS-12, Material: HDPE, ID (in.): 12.26, ID (mm.): 311.4, lbs: 7.2, Kg: 3.27