A component of a gutter system that helps to direct rainwater from the gutters to a downspout and away from the building.

A downspout adapter is a fitting that connects the gutter to the downspout. It is designed to fit over the rectangular end of a gutter and into the top of a round downspout. The overflow feature is built into the downspout adapter to allow excess water to escape from the gutter system (out and away from the building) if it becomes clogged or overloaded with water. This prevents water from overflowing onto the roof or into the building's foundation.

Together, a downspout adapter transition with overflow helps to ensure that rainwater is properly directed away from the building and does not cause damage or flooding.