Our Purple/White engagement spring was rigionally designed in 1990 and was and is the standard for all aftermarket high engagement springs. Our competitors have tried for years to clone this famous spring without success. This allows a high engagment but at the same time allows the primary drive clutch to shift out quickly thus allowing the snowmobile to accellerate faster than our competitors. The Purple/White spring will fit in Arctic Cat, Comet, and Polaris drive clutches. This spring is ideal for drag racing, turbo charged engines and high altitude applications. 175 @ 2.562" and 305 @ 1.3712