This applies to passengers arriving into the USA and connecting to other flights, the Transportation Security Administration (TSA) requires access to air passengers' luggage for security screening in the USA, sometimes without the passenger being present. To allow luggage to be locked for protection against theft, the TSA has approved certain locks, identified by a logo on the locks.
TSA personnel’s can open and inspect your luggage and then re-lock your luggage with the master TSA keys.
If TSA screeners need to inspect your luggage and you do not have a TSA Lock, then they may break your Lock to inspect your luggage and then from that point on, your luggage will remain without a lock, rendering the lock you originally had on your luggage, useless.
Heys TSA Locks can be purchased Here