The Flex2 is an improvement over the Flex-Lite in that the new Flex 2 tree has been coated with DURAhide for more strength and make is resistant to moisture. This new tree also includes Circle Y's new high and low density bars, so that the saddle conforms to the horses back exactly both standing and running. Hence, motion bars for comfort. In addition, the Flex2 skirts have a shock-absorbing neoprene filler to keep the rider comfortable in the saddle on that all-day ride! Equitation Endurance Saddle by Tucker Saddles; this one is for the rider that wants a more balanced equitation seat and all the great GENII innovations! It features English-style strategically positioned 'knee rolls' with padded flaps. http://www.saddledomain.com/Endurance-Saddles-by-Tucker-and-Circle-Y-.html