I've used these for many years. Attached to my flashlights (figured if I can find my flashlight in the dark.. I'm good from there on!), and my keys. I like!!!

Unfortunately getting them in the US is problematic: regardless of how cheaply one can find them in the UK, you can't get them HERE or shipped here easily. Certainly you can't get them legally.

The measurable radiation exceeds US regulations. Period. I've tried to get an import license and submitted a letter from a biomedical nuclear medicine specialist, to no avail.

The last batch I got were sent to me as a "gift" from "somewhere in Europe". I'm curious to see if the DealExtreme delivery even takes place.. but I just ordered a few.