These 6.3mm diameter shark-fin model shafts are available in the following diameters- 110, 120, AND 130. The barb thickness is thicker than typical barb pins; the pin diameter is 2.1mm in the 6.3mm shafts. Each sharkfin has a hole providing three options to connect the shooting line. The shafts are made using 17-4PH heat treated stainless hardened to 47 Rockwell. The new tuned flopper is produced using the same steel (47Hrc) for increased strength. The hole for the pin that holds the barb in place and the pin itself-are recessed completely so they do not protrude from the barb. Thanks to this feature, the penetration in the flesh of the prey is greatly increased. The shark fins are produced by MIM (metal injection molding).