We built the Hydro Tempo-X SUP paddle to be easy to use and remain comfortable over long distances. By slightly increasing the flex of the shaft we can greatly reduce fatigue and paddling injury. To further enhance this, the XL and Large blade sizes come with our Reflex100 shaft, which is a little stiffer and ideal for taller and heavier paddlers, while the Medium and Small blades are fitted with our Reflex90 shaft which is a little more flexible and ideal for smaller paddlers.