I received it yesterday and while I haven''t gone on any trips yet to test these locks out, I did try to set the lock, making up a numerical code. It was easy to do (one needs a pen point or something similar) and the lock definitely stayed closed once one was finished ... until, of course, one set the dials to the correct code. Then it opened easily. It's. nice that they are very lightweight and TSA-compliant .. and that there is no key to lose. Definitely I'll recommend it to my family and friends.