New, unused Pacific Sun Sentry Auto-Top Off with DC pump. This is the ATO that came with my Waterbox aquarium. I'm selling the ATO because I already have the Neptune ATK so this is redundant. Retail for the Pacific Sun Sentry Auto-Top Off kit is $119.99. Link to retail site This unit is tiny! Anyone looking for a small, plug-and-play ATO with an optical sensor would be happy with this. Asking $75.00 shipped.