Casio PRG-50L

Pro Trek design and function for rambling and mountaineers
This model features three sensors and a Tough Solar power system that eliminates the need for battery replacement plus a cumulative ascent altimeter demanded by skilled mountain climbers. In addition to calculating the total ascent, this watch also displays the relative altitude from a selected point. A full Auto EL backlight automatically illuminates the display whenever the watch is angled towards the face while lighting is dim. Following a full charge, the PRG-50 can continue to run for approximately five months if it is operated without charging. If the watch is left in the dark without being operated, power saving feature causes it to enter a sleep mode which keeps it running for about 23 months. The battery recharges and full operation is restored by exposing the watch to light again.
RRP £179.99, only £140