The Hot Buttons work perfectly with the Matthews Doorway Dolly (click to see the Doorway Dolly) or the even more versatile Round-d-Round Doorway Dolly (Click to see the Round-d-Round). For straight or curved rails, in steel, aluminum or PVC, simply remove the locking nut, the self-contained wheel and tire from each axle and replace them with the Hot Button set and nut. The Hot Buttons also allow you to create a perfect scooter trolley with just two axles and any size of ordinary plywood. The combined rail/stage wheels #395001 are as simple to change as the Hot Buttons. These wheels are equipped with self-contained bearings designed to work on hard surfaces or on straight rails of 1-1/2' diameter only.