The two most common styles of finishing a fly are now available in one fine tool. The perfect finisher for trout flies! The TMC Dual Finisher Standard is an innovative fly tying tool which can be used for both whip-finish and half-hitch. The inner diameter of the half hitch end is 17mm (0.67") and works on size 12 and smaller fly hooks..Warning: The tip of the finisher is extremely sharp!