The La Maitre cannons are decent. They use a screw-in CO2 canister for each shot. We've been getting shots traveling up to 45 ft in distance and 25 ft in the air. I use them daily in a rep show and am quite fond of the effect. They tend to be very subject to how they are loaded -- you must do it the exact same way day to day to reproduce the effect (I've seen the payload barely make it out of the barrel due to an air leak or bounce off of the ceiling and get hung up in conduit if things are packed in too tightly). The consumables add up a bit too -- roughly $10-$12 per shot per cannon, depending on the payload.