6" x 2", Mold On Rubber, Rigid Plate Caster, Medium Heavy Duty, 410 LB Load Capacity, Have A Cushioned Rubber Tread Bonded To Cast Iron Core, These Wheels Absorb Shock, Vibration & Are Quiet During Use, Ideal For Most General Medium Heavy Duty Industrial Applications Such As Platform Trucks, Wire Shelving, Other Warehouse Trucks & Carts, For Commercial Use,Bulk.