USED INSIDE AND OUTSIDE THE CAGE -- You can attach it to the outside or inside of the cage according to your own needs. If your pet is naughty, it is suggested to install it outside the cage. And you can easily snap the water feeder on or off for cleaning and refilling. NO NOISE -- This pet automatic water dispenser adopts gravity flow design and can control the amount of water to prevent overflow. It doesnt make annoying noises while your pet is drinking compared to water bottles with ball bearings. Silent design let you have a quiet night sleeping environment. LARGE CAPACITY -- 500ml/17oz large capacity, no longer need to worry about your pet has not enough water to drink if you are not home all day. This water bottle is the great size for Rats, Hamsters,Guinea Pigs, Small Ferrets, Dwarf Rabbits and Other Small Pets. SAFE -- Made of non-toxic and Long-lasting plastic.