A 4 digit padlock is a very secure way to lock a bag or suitcase. A 4 digit combination is harder to guess than a 3 digit combination, however we recommend you do not choose a year for the 4 digit combination, as that makes it easier to guess the combination.
TSA locks allow US customs access to your lock. Customs are entitled to look in any luggage being transported and may cut off locks to access bags. A TSA lock means they have the master key to access the lock, so that they can unlock and relock your bag without damage to the lock.
The keyhole is only for TSA (US customs). You need the combination to open the lock.
The instructions for setting the combination lock are as follows. The original number is 0-0-0. To set your personal combination, follow these steps: Put the dials at its correct numbers (0-0-0 to start with); Rotate the shackle 90 degrees counterclockwise and press all the way down. Hold down and continue to turn another 90 degrees counterclockwise. Set your new combination by turning the numbers. Turn the shackle back as normal. Now you have finished setting your personal combination. Please remember your personal combination or write it down in a safe place. Please repeat the above steps to reset the numbers. You need the current combination to change it to a new combination.