The flexible arm of the electronic circuit drill for carving, engraving and punching, helps to work easily without the need to carry the heavy hammer for a long time. Arm length: 110 cm The diameter of the turning skewer: 18 * 1.5 mm / 19.2 mm How to install it: The iron skewer is fixed to the hammer through the large chuck and then the skewer is inserted The iron inside the arm and attaching the arm to the drill with unscrewing the plastic nut at the front of the drill