Heavy Duty Load Capacity: Industrial casters with thickened steel brackets and sealed double ball bearing design, each casters set of 4 can support load 2500 lbs and are designed for strength and durability under high stress, ideal for warehouse, factory and shop floor use Rust and Corrosion Resistant: These caster wheels 4 inch feature a premium anti-corrosion coating and protective dust cover that resists rust and corrosion, ensuring long-lasting performance in both indoor and outdoor environments and reduce maintenance frequency Smooth and Silent Movement: These outdoor caster wheels are made of durable polyurethane material that provides smooth, quiet movement, is abrasion-resistant and won't scratch floors, even under heavy loads.They are lighter than metal wheels, reducing the burden on operators Versatile Use: These heavy duty locking casters are fantastic wheels for many applications like industrial equipment, workbench, panel trucks, drywall cart, dollies cart, tool boxes, plat-form trucks, large furniture. Our heavy duty quality casters are suitable for most industrial and commercial equipment Quality Assurane: Thank you very much for choosing Humagineer's heavy duty casters, if you encounter any problems with installation, accessories or product quality, please let us know and we will be happy to serve you! Durable 4-Pack Industrial Casters: 4 Inch heavy-duty casters with reinforced steel frames and dual ball bearings, designed to support loads up to 2500 pounds. Built for long-term use in demanding environments like warehouses, workshops, and garages. Key Features: ◆ Corrosion-Resistant Design Zinc-coated steel brackets and rust-proof components withstand humidity, spills, or outdoor exposure. ◆ Quiet Rolling & Floor Protection Thickened PU wheels with non-marking treads minimize noise during movement and prevent floor scratches. ◆ Reduced Maintenance Sealed dust covers protect internal bearings from debris, while smooth-rolling construction requires no lubrication.