Swix Racing Diamond StoneX Coarse is best for beveling your edges and for repairing after the edge hits a rock. Coarse is one of the main ones you should own for beveling and repairing edges. Medium is the second must have file for well performing edges as it gives you a good general finish for most skiing. Fine is an extra step for a great finishing polish which extends the life of your filing. X Fine is the finest file for the finest of margins; it gives a mirror like