Gutters act as a part of a rainwater drainage management system. Uncontrolled rainwater from the roof can damage your foundation, cause siding and wood rot and encourage interior mold and mildew. Bent at an angle that faces the front or back of the gutter system. Use this elbow with gutter components sized for 3 in. x 4 in. rectangular shape. - Amerimax Gutter Front "A" Elbow, Aluminum, White, 3 in. x 4 in.