Garmin foretrex 101.
This is I believe one of the first wrist mounted GPS units Garmin produced and is now outdated by the 301 and the 401.
It’s not often I use a GPS but they do have there place certainly in the military. This think has had a life time of use from, Afghanistan to Canada to all over the mountains in the UK. It is now a regular use item in my search and rescue kit. ( alongside a map and compass of course )
I also use this when out geocaching with groups from work, and is a great way to teach the use of a GPS.
All in Garmin make some fantastic products with there GPS units being some of the best on the market.