Twin Air 160742 Powerflow Throttle Body Kit for Husqvarna FC 350/450 14-15/KTM 350 XC-F/450 SX-F/XC-F 13-15Get faster, smoother throttle response where you need it most. Installed in your throttle bodys Venturi tube, the precision engineered sleeve reduces the diameter and accelerates the velocity of your air fuel mix. Add the thinner butterfly valve and less obstructive shaft, and youve got faster, more even throttle response through low and mid range. For better top end throttle response (90 100% open throttle position), use the kits larger butterfly