Carbon Express Nock End Weight Adjustment Wrench Easily change the screw-in weights on large diameter target shafts Inserts in the nock end of shaft to avoid removing points Works on all Carbon Express threaded point weights with a 3 mm allen hex easily change the screw-in weights on the large diameter target shafts by simply removing the nocks of the shafts, inserting the wrench in the nock-end and adding or removing the weight.