A TSA lock is a luggage lock that can be opened not only by its owner but also by TSA agents at U.S. airports. TSA stands for Transportation Security Administration, which is an agency of the U.S. Department of Homeland Security. TSA locks are designed to allow security authorities to inspect luggage without damaging the lock or the luggage. TSA-approved locks can be opened by the authorities using publicly known universal "master" keys. Locks using this system are produced to meet standards set by Travel Sentry, which is a group that develops and approves designs for TSA-accepted locks. TSA-accepted locks can be identified by the Travel Sentry symbol, which is a red diamond. TSA-accepted locks are recommended by the TSA, as luggage locked using other methods must be opened by force in order to be inspected.