A padlock is one of the oldest and the most common tools to protect our personal belongings. It can be used for securing lockers, window ands, doors, and cabinets.
Since the invention of padlocks, people have been using padlocksthem to protect their lifves, bodyies, property, and privacy. Those are the personal securities which are in human psychological needs that were expressed by a psychologist (Maslow, AH). Therefore, instead of out of step with today’s society, the padlocks' features and quality are being betteimproved.

According to the Hong Kong Merchandise Trade Statistics- Domestic Exports and Re-exports, the quantity of “padlocks and locks, base metal; clasps, etc. incorporating locks, of base metal;s are key” exporteds to China in January to July 2016 is- 1,589 kg and to the United States of America in January to July 2016 is 371 kg (Table 1). Also, the total quantity of “padlocks and, locks, base metal;s and clasps, etc. incorporating locks, of base metal;s and key” re-exported to the world is 12,114,235 kg. (Table 2) Based on the statistics, the padlocks are still in great demand inthroughout the world.