These heavy-duty optional casters can be added to the base of most electric tables or hydraulic grooming table in place of the leveling-feet to make the table mobile. Wheels lock in place to keep the table stationary and unlock for easy table relocation. The casters are made of rubber, steel and raise the table 4-1/4-inch. A set includes four casters. Measures 8-4/5-inch length by 8-1/2-inch width by 3-1/2-inch height.