Polyethylene Sheet HDPE 2mm-m-4mm-5mm-6mm-8mm thick – Suppliers High Density Polyethylene Sheet: 2mm to 8mm thick. On this page you can buy High Density Polyethylene, also referred to as HDPE or PE300, in full sheets in 2mm, m, 4mm, 5mm, 6mm and 8mm thick.