Let me start by saying this little alarm packs a SERIOUS punch when it works properly. The 120db scream is genuinely startling - I accidentally set it off while testing on my apartment door and my neighbor came running thinking there was an emergency!

The good: It's lightweight and easy to install anywhere with the included adhesive strips. I've used it on my hotel door during a business trip (felt much safer) and on my backpack in crowded areas. The ABS plastic feels durable enough for travel.

Now the frustrations: The sensitivity is all over the place. Sometimes it goes off if a fly lands on it (not kidding), other times you can shake the whole door without triggering it. The switch is ridiculously stiff - I nearly broke a nail trying to turn it on/off.

Biggest complaint? The 'instructions' might as well be hieroglyphics. Took me 15 minutes to figure out battery installation (yes, you need to supply your own). Also noticed the alarm volume seems inconsistent - probably a battery drainage issue.

Final verdict? For $10, it's decent emergency protection if you're traveling sketchy areas, but don't expect premium quality. Buy 2-3 since reliability is questionable.