Founded in 1921, Master Lock is recognized around the world as the largest producer of padlocks, selling approximately 50 million locks each year. Master Lock is one of the largest global manufacturers and marketers of padlocks to the sportsman, home and yard, school and commercial markets, and dominates the school locker lock business. The company has also recently entered the automotive, computer and private label security markets. All Master Lock products are individually tested for quality and each padlock has a full lifetime guarantee. Master Lock is also the only padlock manufacturer with national multi-media advertising support in television, radio and print formats. Master Lock Company has offices in Milwaukee , Wisconsin.