This is a whistle that sports a compass on one side and a thermometer on the other. Not shown is the lanyard it comes with. I have not calibrated the devices so I can't speak to their accuracy but it is a handy wear-around-your-neck tool when you just want a quick check or if you don't need to carry a more accurate tool. I wouldn't substitute it for a serious compass if you plan on being out in the wild, but as a handy little aid it's a great idea. 3 stars