Casio PRG-80L-3VER

This mountain watch weighs 76g; solar power so no need for batteries; barometer; altimeter to 10,000m, temperature; digital compass; water-resistant to 100m; 29 time zones; 5 daily alarms. But like some other watches temperature range is only down to -10 deg C; the styling is very aggressive; solar power inflates the price.

Verdict: Buy it if you don’t want to worry about battery failure ever again but do want a fully featured mountain watch.