The inline diverter is designed to use a water barrel to collect rainwater. The water can then be used on sunnier days. Giving you that gardener feeling and conserving both resources and money. Simply fold out the tongue when you wish to collect water, and fold it back up when the barrel is full. With the tongue folded up it works just like a normal downspout. The inline diverter has an expanded top and preshrunk bottom end. This makes it fit perfectly into the downspout. Like all other downspout related products, the overlaps are 2". There is no need for caulking or putting any rivets or screws into the inline diverter. This keeps the inside of the product smooth and water flows freely.