Plastic strip is generally used for 20° - 22° framing nails. They are held together by a strip of plastic that breaks apart when fired by a gun. They are less expensive than other types of collated fasteners (plastic coil or paper strip) because they are easier to manufacture. They can become very brittle when cold, and the residual plastic must be disposed of. Pieces of plastic are sometimes left under the head causing the nail to be exposed.