Flat-Free Polyurethane Foam Wheel, 500 lb Load Rating, Smooth Tread, 15 1/2 in Wheel Dia., 3 5/8 in Wheel Width, For Axle Size 1 in, 4.80/4.00-8, Standard Tire Rim Type, Center Mount Hub Position, 6 in Hub Length, Steel Hub Material, Yes Non-Marking