Offers maximum performance Made with Boyesen s patented dual stage fiberglass design for more airflow delivering more usable power than stock reeds Manufactured with Boyesen s exclusive DURA *FLEX material Your original one stage reed operates most effectively only within a narrow RPM range while Boyesen s one soft reed on top of one firm flow through reed gives you a wide range of intake control plus increased intake velocity Minor change gives major H.P. improvements Top reed opens at lower RPMs allowing for more air and fuel flow giving you better throttle response Bottom reed opens at higher RPMs for maximum flow Faster opening and closing Greater low pressure (low throttle) response Greater velocity and flow area No engine damage if broken Longer overall life Matched to O.E.M specs More air velocity equals more overall power Note: Two sets required for part number 304-0645. Image for reference only. Actual product may vary according to vehicle.