Muvtons premium soft durometer polyurethane threaded wheels 83° ±3° shore a, firmly bonded to precision machined cast iron cores. These wheels have been designed to response to noise problems and allow loaded to be cushioned. The use of lively polyurethane materials allows these wheels to flex & roll over debris and obstacies without picking up objects. They are non marking and floor protective. Tested & guarantee against bond failures. Wheel bearing options : sealed precision ball bearings, tapered roller bearings or roller bearings. Temperature range; -20°c to +85°c. Thread options : anti static : conductive wheels are available.