I got this PetSafe Drinkwell pet water fountain for my pets. I chose the 1 gallon size because one of my pets is a very small dog and it's also for my cats. This fountain is low enough for all of my animals to reach and they all love it! I found that I am constantly filling up my pet's water dishes so I thought a water fountain would be nicer and hopefully stay full longer, which it does. I also feel better feeding them filtered water. This fountain was very easy to set up. It came with great, easy to understand instructions (with pictures).