Maintaining the water level in your golf cart batteries is a vital task, but it can also be a time-consuming hassle. With the Pro-Fill On-Board Battery Watering System, refilling batteries on an entire cart takes a minute or less! It connects to a single water supply and evenly distributes water into each cell at the same time - no more individual pouring. Won't overfill your batteries - it automatically determines how much each battery needs and fills accordingly