On Electronics Woot right now http://electronics.woot.com. The Tracker, for $15 (list price $32). It claims a range of 150ft using Bluetooth 4.0, works with Android or iOS software to let you track or find objects, alarm if they get out of range, or alarm if they get in range. Obviously it would be the tracking we're interested in! If you have one of these -- the size of a quarter (U.S. coin) on or in your quadcopter and it goes down (or into a tall tree), you may have a lot easier time finding that $100+ bundle of parts with THIS than just your eyes. The claim is the battery lasts a year, so you've got plenty of time to TRACK IT DOWN. I ordered THREE. At that price, why not? The product is more commonly known as a STICKNFIND and there are many reviews of it on YouTube.