High-volume vertical check valve located in the QS3 for precise, consistent fuel meteringTunable leak jet maximizes volume of fuel and duration of fuel spray for all conditionsIntegrated Hot Start Assist eliminates problem 4-stroke hot start procedureThe most effective way to add performance to a Keihin FCR carburetorPatented design stops bogging and improves throttle responseInvestment cast and finished to precise tolerancesImproved low-end performanceSimple bolt-on installation25% more fuel capacityFor all Keihin FCR-Equipped MX, Off Road and ATV models.