The Hopper Topper fits any standard 30 gallon paper lawn & leaf bag. With its large funnel-shaped opening, the Hopper Topper directs the flow of yard waste into the bag and not all around it...even under windy conditions! The HopperTopper keeps the mouth of the bag open that allows laying the bag flat for easily raking leaves and debris directly into the bag. The bags can be packed down easily without having to remove the Hopper Topper.