These elastic straps were specially developed for the FENTO MAX. Do you work with sand a great deal? Then we recommend these clip-on elastic straps rather than the Velcro elastic straps. You can easily replace your elastic straps once they become worn. This makes the FENTO MAX much more sustainable. They are strong, wide elastic straps that are tied around the calf and therefore do not pinch behind the knee. The clip elastics of the FENTO MAX are also applicable to its former model: the FENTO 400.