Polypropylene core with no ribs to allow easy cleaning. Polyurethane injected tread bonded to the polypropylene core using a mechanical system preventing debonding. Provide good floor protection. Non-marking. Light weight, resistant to impact, shock, abrasion and wide range of chemicals. Performance proven in wet and corrosive conditions. Dimensions: 4" x 1 1/2" to 8" x 2" (100 x 38mm to 200 x 50mm) Load capacity: 400 to 1,000 pounds (182 to 455 kg) Standard colors: Red and burgundy Also available: Swivel and rigid casters 4" X 1 1/2" to 8" x 2"