Greater flywheel mass = a more realistic ride! Add the Pro Flywheel to any Kinetic Fluid Trainer manufactured after January 1 2010 ( or a serial number higher than 76184) and you will experience longer spin ups and when doing sprint intervals and longer coast down times.
Note: The Pro Flywheel will not work on a Rock And Roll trainer (T-016) when used with a Small Wheel Adapter (T-500).