My 25+ year old shop vac had the cheap plastic dolly go bye-bye so I cut a circle and square of particle board and glued them together. Casters on the bottom of the square and two HD magnets set flush with the top of the circle which fits inside the welded seam on the canister. Of course this won't help the newer all plastic units but it does the job on my antique. Gerry :-)} London, Canada