I'm utterly hopeless with keys, specs and my purse, so this little gadget is very useful - and it works! I've tried other devices but they have proved to be pretty ineffective - this is much better. The noise is audible through walls and I have already successfully retrieved my my specs (attached the tracker via an elastic band to the opening of the case) and keys from several forgotten dumping grounds around the house. Not cheap but it does the job. Thank you.