The third test of sending a GPS device through the post. This time it is a Polar GPS watch. The tracking is constant from when I switch it on, and lasts about 14 hours. It tracks every step of the route, and produces glitchy scribble when its inside without a GPS signal. I posted it on Thursday, and when I opened the parcel on Sunday evening the watch said it has 3% of battery left, but it had stopped tracking long before that.