5 heavy-duty urethane casters that last longer and roll smoothly over cracks. Two of the casters lock, holding your bucket in place even on steep inclines. Rugged Bucket Dolly supports up to 250 pounds and is securely held in place with three thumb screws. Dolly will fit most 3.5 gallon, 4 gallon, 5 gallon and 6 gallon buckets.