BottleFresh(TM) tablets use an effervescent bubbling action formula, which penetrates deep to dissolve the residue, dirt and grime that builds up in your reusable water bottles. Our convenient pre-measured tablets deliver a powerful, sparkling clean that you can see and taste. The fast acting bubbling action starts working immediately and leaves behind a fresh, light and clean mint scent. BottleFresh(TM) tablets are safe to use with no harmful chemicals and they won't create any dangerous by-products as all the active ingredients revert safely and cleanly back to oxygen. Our tablets are environmentally friendly and biodegradable. Use once a week or more/less frequently as required based on usage. 2 Packages of Bottle Fresh(TM) contain 20 tablets.