Take the guesswork out of nock positioning. Secure your bow in a vise, clip on the String Level and adjust the vise until the bow is at horizontal and vertical level. Place the nock arrow on the rest and attach the NOK-EZ Level to the arrow.
Slide the arrow up or down on the string until it is level. You've now located the perfect 90° nock positioning needed for precision tuning. Combo includes NOK-EZ arrow level and String Level.