After the great success of the original TC Pro Matched Spring Sets,a 4step softer range has been added to widen the setting possibilities. The spring rates of any single spring can be slightly different even if made from the same wire rod with the same number of coil. This is why each piece of the TC Pro Matched Springs - SOFT version has been individually measured and matched as a pair to provide the guaranty of a strictly identical stiffness rate value. Atsushi Hara supervised the stiffness rate value. Total length 25mm, an inner diameter of 14mm