Whether for home, farm, builder or industrial customers, National has all the right hardware in the sizes and finishes you need. With over a century of service National is committed to maintaining the highest level of product quality, innovation and manufacturing technology. Providing a reliable barrier against unauthorized entries. Barrel bolts add additional security and are made in standard, heavy duty or extra heavy duty versions for indoor and outdoor applications. A proprietary Weather Guard zinc coating is three times more corrosion resistant compared to the competition.