The red alert indicator on the top of luggage lock will pop-up once the lock is opened by TSA agent, it alerts you that your luggage has been inspected. The indicator will return to the original position when you open the lock with your combination. Easy & Convenient: The resettable 4 dial TSA combiantion locks allow you to set you own combination with 10000 unique choices. No keys needed. Setting or Resetting is easy following the instructions which are always included. Flexible Cable Design: Unlike rigid locks, the TSA cable locks are flexible to thread through all standard sized zippers and hard case lock holes. At a total length of 5in, the reinforced cable can link 2-3 sets of zippers at one time to secure the entire case/bag. It is designed to be plastic covered so it won't scratch your luggage. They are best travel locks.