Thenew refined aluminum foil section gives the best balance between light weight and increased strength for higher loads. The AF72 Mast is 30% stiffer than the AK70 (AK = Alloy Kite) mast yet only 13% heavier, and is ideal for shallower waters, and prone surf foiling.The AF85 Mast is 30% stiffer than the AK85 mast yet only 13% heavier, and it increases overall ride performance in choppy conditions.