Seems like quite a few folks put a tracker device on their copters. Which one seems to be the lightest weight and most reliable for the cost? Seems like there is a heck of a variety out there from tracking luggage, to kids, to pet collars (hunting dogs for example). Are there any that have stood out amongst yall for their weight to function ratio? Devices range from audible alarms (press a button and the kid tracker beeps) which would help finding the copter if it were down in tall weeds. Others have directional beacons to home in on. Thoughts?