The toilet tank bank is a great way to use less water and reduce your water bill. Just fill the tank bank, put it in the toilet tank and leave it. It's a one time deal, and you're not going to have to think about it again (except when you notice your water bill is lower). The toilet bank is an easy device to use for water conservation. Just fill the toilet tank bank to the top, snap closed and hang in your toilet tank. Because it takes up the space of the water, your toilet works just as it would normally. The toilet tank bank keeps your toilet tank full so it doesn't have to refill with new water. It saves water with every flush, up to .8 gallons a flush. It’s made of non-corrosive materials which resist microbes and fungal growth. The airlock on the toilet tank bank means that the bag never needs refilling. Only $1.95.