The blades are made with an ultra-performing carbon fiber of incredible strength and flexibility. The fabrication of this carbon fiber is done with a high vacuum 100% industrial procedure, to obtain an exceptional compactness of the carbon fiber. Average carbon fiber used for fin blades in the industry has 3. 000 fibers per thread. Our carbon has 12. 000 fibers per thread. Four times as much. Four times the resistance. Four times the flexibility and elasticity, kick response compared to other carbon blades on the market. Each thread in this carbon fiber is very very small. So small that the total density of the blade is an incredible, and unmatched, 20. 000 fibers per square millimeter. Xld - high flexibility blade dedicated to those divers who prefer a very soft and smooth fin. It is indicated if your fishing sessions include long sessions and if you cover long distances. Md - medium flexibility blade it is perfect if you fish using a boat to move from spot to spot, using a constant weight. Hf - stiff blade it is ideal for strong, powerful athletes with a higher bodyweight. It is also useful in waters with strong currents and when fishing in rougher sea conditions