BOYESEN DIRT BIKE PRO SERIES REEDS.Pro series dual-stage reeds combine a carbon-fiber top reed with a fiberglass bottom reed for unrivaled performance.The Pro Series are more responsive than our traditional power reeds.The carbon-fiber top reed has excellent response characteristics that provide even quicker acceleration stronger throttle response and more over-rev than our standard power reeds.The fiberglass bottom reed provides stability and longer reed life.