Shackle padlock of size 3 millimeters by the company Osprey, suitable for locking small-sized items such as suitcases, drawers, etc.. The locking and unlocking method is done by the combination of numbers on the lock. You don't need to carry keys but you definitely need to remember the combination. Comes with TSA certification, which essentially allows security authorities (e.g., airports) to unlock and inspect your luggage without damaging it.