Abstract: A fastener for coupling a first object and a second object comprises a base, a bending portion and a through hole. The base includes a hole and binds with the first object by a fixing component passing through the hole. One end of the bending portion is extended from the base in a curved U shape. The bending portion has a plurality of ribs, and one end of the bending portion warps away from the base. The through hole is formed between the base and the bending portion. The second object is disposed in the through hole by bending the bending portion away from the base to expand the bending portion outward. The bending portion clamps the second object when the bending portion is released to its original state. Therefore, the fastener can bind and separate the helmet and the mask without any assistance of a tool.