Plastic strip is generally used for 20 through 22 degree framing nails and 15 degree coil nails. They are held together by a strip of plastic that breaks apart when fired by a gun. They are often cheaper than other types of collated fasteners because they are easier to manufacture. However, they also leave a mess of plastic around the job site and can become very brittle when cold. They can also leave pieces of plastic under the head causing the nail to be exposed.