See detail @ http://www.amazon.com/gp/product/B000RTBRB0/?&tag=externalharddrives0a-20 The 70 oz. Additional Capacity Reservoir Plus is an optional attachment for the Original Drinkwell® Pet Fountain. With use of the Additional Capacity Reservoir Plus, the system provides over a gallon of fresh filtered water which is perfect for dogs up to 50 lbs. This product cannot be put in the dishwasher.