I have a similar unit, made by Coghlan’s, with out the LED light, that includes a whistle, magnifier lens, thermometer, compass. While using it on a desert hike I made the following observations. 1) The compass did not correctly point to Mag North, using known landmarks and a current topo map as reference. 2) The thermometer “POPPED” after being exposed to 90+ degree heat and direct sun, it was clipped to a zipper pull on my pack. 3) The magnifier was ok for looking at the native flora and fauna. 4) The whistle worked as well as anything out there, but the sound is always good in desert canyons. The gadget factor for a young outdoorsman, PRICELESS!

Regretfully, I can claim to owning one of these things. Saw it a few years ago at American Science & Surplus in Milwaukee (visiting the parents) and bought it. It was like 2 bucks. Figured I could try it out instead of eating another 2 double cheeseburgers from McDonalds. It isn't a bad things to have. Can't say I have used the compass or thermometer on a regular basis, but the whistle is relatively loud, not Fox 40 loud, but not bad. The light is still working also. It's my "nightlight"/flashlight when I have to go to the bathroom and don't want to wake up the DLW (that's Dear Lovely Wife) by having to turn on bedside light.