at any kitchen store you can buy these, you can buy Nitros Oxide cartrages at these stroes too, but you have to be 18+ but i agree unless you hooked it up to your engine with 50+ cartages at once, it wont do good, might make a big sharp explosion in your engine for a slpit second.... harming your motor. Save money with this kit, and use the rest of your money on a new engine.... or just get a ZEX kit, and call it a day