Clutch Spring Kit Coil Spring Csk Series Steel CSK125Spring SetThese are spiral wound springs using 4 8 pieces per set made from heat treated high carbon steel and come in various shapes and sizes delivering differing spring tensions depending on the size of the bike and the horsepower of your engine. It is important to note that you cannot change the basic shape of these springs to gain any performance advantage but what you CAN do is buy a EBC Brakes CSK kit which have slightly ticker winding material