Fits all 2012-15 Pro Chassis Arctic Cat models.Improves acceleration and increases top end speeds / track speedDrastically decreases clutch and belt heatImproves belt lifeAllows full overdrive shift-outSmoother upshift, quicker throttle response, faster back-shifts Kit includes: Helix with adjustable end cap and torsion springplease contact us with application so we can help choose the correct set up for your sled