Performance carbon fiber reed valve, most commonly (but not exclusively) used for liquid cooled 39cc, 47cc and 49cc 2-stroke engines on a wide variety of pocket bikes, mini bikes, mini dirt bikes, mini ATVs (mini quads), mini choppers as well as many other powersport and mobility products. This carbon fiber reed valve delivers maximum power for your liquid / water cooled engine. A performance upgrade for many models of 2-stroke machines.