Think of a Tacony tandem air vacuum as a "monster" vac you can buy.It is the same idea as some vac collectors by pairing a Kirby or some other direct air upright with a central vacuum,NSS M1, or another canister vacuum.The direct air fan close to the flooring surface being cleaned-and the clean air fan after the bag and filters.If you want a "monster" vacuum you don't have to make up-the Tacony Simplicity-Riccars are excellent choices.I still use a separate canister,though even if you can use the Simplicity-Riccar machine as a "canister".Its just awkward to me.-But it will work.The Tacony machines have it over a Kirby for canister use-no worry of quarters,pebbles,and such going thru the direct air fan at max motor speeds.You just can't pick up large,long items with those of they will clog the airpath.Such as pens or popsickle sticks.Beleive me at the vac shop-folks have tried!!You need a commercial canister or Shop Vac for those things.