One of the fundamental upgrades you can make to your scooter is swapping out the clutch springs for ones that will give you more acceleration off the line.The different colors are different stiffnesses to allow you to dial in your scooter to just the way you like it.These springs are great for the beginning tuner or the advanced looking for more control over the performance of their scooter. Three springs come per set. (photo shows all possible colors of springs)