Yellow Color,1500RPM, 3pcs of Clutch Springs & 1 Torque Spring The lowest rated 1K Springs may give you a higher speed overall but will engage at a lower RPM on take-off. Hard to “climb the hill” The 2K Springs will give you the greatest grabbing power and a higher RPM at take-off.Easy to “Climb the hills” but may be slower in speed overall The 1.5K springs have the balanced performance. Please Note: The exact performance of upgrade parts will be affected by many other factors Product Description 1.New Products with High Quality 2.Replacement for GY6 150cc Stock Torque and Clutch Springs 3.Fits Most of Chinese Made Scooters and ATV. Such as JONWAY, JMSTAR, ROKETA, SUNL, TANK, PEACE, TAOTAO,JCL,Coolsport,Kazuma