Just a few drops help prevent the resin from building up. It keeps our pieces clean, and our hits fresh and delicious. When you add RezBlock to your water, it prevents the resins from sticking to the glass and instead they float in the water allowing you to pour out that gunk along with the ash and other particulates you don't want. RezBlock is completely organic, which means you'll need to change your water out regularly. With RezBlock and regular water changes, you'll see drastically less buildup in your bong. Up to 60 uses per 15ml bottle.