A fastening device includes a tube defining a first axis, a tube first end, a tube second end, and a through hole, the through hole defining a first opening and a second opening, a second axis of the through hole being substantially perpendicular to the first axis of the tube, the tube second end of the tube securing rigidly to an attaching device. The fastening device also includes a cord inserted through the through hole, the cord defining a cord first end and a cord second end, the cord first end disposed on a side of the through hole corresponding to the first opening, the cord second end disposed on a side of the through hole corresponding to the second opening. The cord first end is looped over the tube first end of the tube.