It’s one of the most precise jigs on the market for vanes up to 2-1/4" long. With a simple flip of the lever, it perfectly places three vanes at once 120° apart, at 3° right helical. Fletches almost any shaft, including crossbow bolts. Helix Tower comes with five center post options fitting standard carbon, A-nock, F-nock, pin nock and crossbow bolts. Arrow nock must be removed prior to fletching. Not for use with swedged-end arrows.