We use two sizes/brands of pumps to accommodate the larger and smaller fountains. After testing every pump available we selected these for their durability and quietness, and we test each one of them again.
Please note that they are not interchangeable and though it should be easy to tell which you have please be sure to contact us if there is any doubt when time comes to replace the pump. (Probably not soon. There are fountains with the original pump that have been in use for over ten years.)