High-Quality Polyurethane on Polyolefin Casters crafted with premium polyurethane treads and high-impact polypropylene cores, these heavy-duty caster wheels are highly durable and resistant to chemicals, oils, acids, grease, and water. Designed for long-lasting and smooth performance in demanding environments. 4-Inch Heavy-Duty Caster Set: Caster Diameter: 4 inches Width: 2 inches Top Plate Size: 4 x 4.5 inches Total Height: 5-5/8 inches Load Capacity: 600 lbs per caster, 2400 lbs per set of four 5-Inch Heavy-Duty Caster Set: Caster Diameter: 5 inches Width: 2 inches Top Plate Size: 4 x 4.5 inches Total Height: 5-5/8 inches Load Capacity: 800 lbs per caster, 3200 lbs per set of four 6-Inch Heavy-Duty Caster Set: Caster Diameter: 6 inches Width: 2 inches Top Plate Size: 4 x 4.5 inches Total Height: 5-5/8 inches Load Capacity: 1000 lbs per caster, 4000 lbs per set of four 8-Inch Heavy-Duty Caster Set: Caster Diameter: 8 inches Width: 2 inches Top Plate Size: 4 x 4.5 inches Total Height: 5-5/8 inches Load Capacity: 1250 lbs per caster, 5000 lbs per set of four Precision Ball Bearings: Integrated precision ball bearings ensure enhanced load capacity and smoother rolling compared to standard roller bearings, providing effortless mobility. Versatile Applications: Suitable for industrial and residential use, these casters are perfect for panel trucks, drywall carts, U-boat platform trucks, lift tables, dollies, and more. Designed for both indoor and outdoor environments.