This can be bundled with the Original Drinkwell Pet Fountain which is also in my listings. It adds the capacity of 50 more ounces of fresh, flowing water for your pet. It is easily added to the back of the fountain and is great for ensuring that your pet’s water supply stays full and fresh. This one is a replacement for the one we used. Note: the plastic canister should not be placed in dishwasher…or at least on the bottom rack. There are two lids and holders due to my error with our first canister. Works for cats or dogs or any other pet who will benefit from fresh flowing water. Increase the capacity of your Drinkwell Fountain. With these convenient reservoir add-on's, you can more than double the amount of water held in your fountain. Now it will last longer between fillings and make the unit more suitable for larger animals or multiple pet households. Choose from either the 50oz or 70 oz size depending upon your needs. This accessory is easy to install, and will greatly increase the value of your Drinkwell Fountain. Just pop it on and you are ready to go. Give your pets the fresh, clean water they deserve and do it even easier with an extra capacity reservoir. For use with Original Drinkwell Fountain.