Product name: Arrow InspectorMaterial: ABSSize: about 26 * 8.5 * 8cm / 10.2 * 3.3 * 3.1inch 1Feather and Vane Check: Excess glue at fletching time could cause an arrow to be out of balance .To check for featherand vane balance, place arrow on the Arrow Inspector and rotate slowly. Leave arrow in one position . If arrow rotates, inspectthe vane or feather that faces downward . A well balanced arrow will romain stationary when rotated to anyposition on the Arrow Inspector. 2Arrow Balance Check:Spin arrow with broadhead in arrow, if you see a wobble , most likely the shaft is not straight,or the insort is glued in crooked. 3Field Point Check: Spin arrow with feld point in arrow and check for straightness.