Whether for home, farm, builder or industrial customers, national has all the right hardware in the size 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 weatherguard zinc coating is three times more corrosion resistant compared to the competition.