PACKAGE: Included 4 Heavy Duty Low Gravity Center Rigid Casters（Free Bolts, Nuts and Washers) DOUBLE WHEELS & LOW-PROFILE: 1'' Diameter Double Wheel Caster--41mm Widened Wheel Make It Easy to Veer. Low Centre of Gravity to Improve the Stability of Your Furniture/ Equipment. LOAD CAPACITY: Total 1100 lbs (275 lbs each caster) MATERIALS: New Premium Nylon/ Industrial-Strength Thickened Steel UNIVERSAL: These Low Profile Caster wheels Not Only be Perfect Caster Replacements. Also Ideal for DIY Furniture(sofa, bed, island cabinet), Workbench, Toolbox, Appliances(freezer, washer, dryer), Pianos, Electronic/ Laboratory /Medical Equipment, Machinery or any other you need move it easily and roll smoothly but not too high. Easy your life and Save your labor & time. PACKAGE: Included 4 Heavy Duty Low Gravity Center Rigid Casters（Free Bolts, Nuts and Washers)