This operates just as the instructions indicate. I am very satisfied--especially with not having to do the necessary mathematical calculations so as to ensure the correct amount of chemical indicated. Simply pour any quantity in the container, dial to the proper setting, and spray away, feeling confident that there is no over or under application. After finishing application, pour the remaining liquid into the original container (liquid chemicals only). Having been a licensed applicator/operator in the professional industries, I strongly advocate this for anyone serious about the proper treatment of chemical to his plant life.