Abstract: A device is provided for binding together sheets of paper formed with two or more spaced holes and attaching the same to a folder or the like. The binder preferably is injection molded of a semi-flexible material and is formed with a flat backing plate and at least a pair of stems which initially are parallel to one another and perpendicular to the backing plate. The stems are spaced apart by a distance equal to the spacing between the holes in the paper and are formed with co-operating male and female elements along the length thereof which allow the stems to be folded one against the other in locking engagement. Each stem is provided with a hinged stop at the free end thereof, which stop folds in against the stem while papers are being inserted or removed and swings out perpendicular to the length of the stem to prevent accidental separation of papers from the stem. Extension pieces are connectable to the ends of the stems and are provided with stop means at the ends thereof.