Manifold has a full 55 mm diameter intake opening for more airflow. Lets your engine breathe better - a must-have upgrade for 124” and larger engines. CNC-machined T6 heat-treated cast aluminum construction. Adds horsepower. More heat-resistant than the OEM polymer intake manifold. Includes new rubber O-ring seal. Made in the USA. Fits 17 to 24 M8 except 23-24 FLHXSE, FLTRXSE, 24 FLHX, FLTRX, FLTRXSTSE. Replace stock oem which tends to leak and wrap.