Thickness: 20mm ± 2. = 1 inch; Weight: ±1450 gr. = 3 pounds and 3.15 ounces; About HDPE: HDPE is known for its large strength-to-density ratio. Therefore, the density of HDPE can range from 0.93 to 0.97 g/cm 3 or 970 kg/m 3. Although the density of HDPE is marginally higher than that of low-density polyethylene, HDPE has little branching.