The Yost Pro Power Tube produces a very fine mist by design. This allows the fuel to stay in suspension longer for better control of air and fuel mixtures and can be almost perfectly matched for any throttle position. You can expect an increase of up to five H.P., improved mid range performance, and an incredible throttle response. Each kit comes complete with an emulsion tube, Yost Power Tube that is press fitted into the emulsion tube, Blue and Red needles, 1/8" drill bit, 7/64" drill bit, compression spring, 165, 175, 185, 195 main jets, and washers. Fits the Keihin CV carburetor as stock on 1988-2006 Sportster, 1990-1999 Evolution Big Twin and 1999-2006 Twin Cam.