Liquid cast quality polyurethane chemically and mechanically to a strong polyamide core. Non-corrosive & non-marking 95° shore a, non-staining, abrasion-resistant, floor-saving, low-noise operation,low rolling resistance tested & guaranteed against bond failures. Wheel bearing options: sealed precision ball bearing or roller bearings. Temperature range:-20°c to +85°c. Alternatively available with soft polyurethane tread.