This is an upgraded 3 fletch, or 120º, knob for your Vane Master PRO fletching jig. Not only can you fletch 120º, while aligning your nock with your cock vane up, but you can also fletch 120º and have your cock vane align at 90º for recurve shooting. This knob can be attached exactly like your other knobs and can take the place of your original 120º, or 3 fletch, knob. This knob will now be standard on all Vane Master Pro shipments from August 3rd, 2016.