These wheels are solid white nylon. They are exceptionally durable, have high impact resistance and are excellent for wash-down & applications that may require steam cleaning. The white color is preferred by industries requiring a clean evironment, dirt and grime show up easily if missed in cleaning. Applications may include: pharmaceuticals manufacturing, food processing, restaurant equipment, slaughter houses, meat packing plants, institutional and medical environments. Available with roller bearings, delrin bearings and sealed precision ball bearings. Durometer: 70 to 75 Shore D. Temperature Range: -45 to +200 Degrees / F.