Lightweight aluminum or brass. Steel Shackle. 2 keys included. Using Travel Sentry® approved lock allows your luggage to be unlocked and inspected by security authorities without damage. Each lock has a special code, which is used by the TSA and other security agencies to know which tool to use to open the lock. Every security screening location at all U.S., Canadian and now many other international airports are able to open the lock and then safely relock it after inspection.