Products Main / HVAC / Risers Angle Flat Risers Angle Flat Angle * 90°45° Angle Choose an option90°45°Clear Risers Angle Flat quantity Add to cart Description Redirects airflow horizontally. Available in 45° and 90° styles. Frequently Asked Questions How do you turn a duct sideways through 45 or 90 degrees? Flat angle risers redirect airflow horizontally through a 45-degree or 90-degree duct transition.