Solar power, triple sensor PRO TREK: This new edition to the PRO TREK range is an essential piece of equipment for those who love the outdoors or have an interest in outdoor pursuits. This watch is powered by a tough solar power system which eliminates the need for batteries. The analogue-digital configuration means you can always check the time even while viewing digital data. A trio of sensors provides up-to-the-minute readouts of barometric pressure and altitude (-700 to 10,000 meters), air temperature, and bearing. All of this and more makes the new PRG-60 a serious adventuring tool that's just the thing for challenging the great outdoors

Key Features: Water Resistant 100m; Solar power; Digital compass; Altimeter; Barometer; Thermometer; Low temperature resistant; Electro-luminescent backlight; 1/100 Sec Stopwatch; Daily Alarm; Titanium Bracelet.

Price: £239.99
There are cheaper versions of this range available with slightly less functionality.

Radio controlled SEA PATHFINDER: Is CASIO's ultimate marine watch ideal for anyone involved in diving, boating or any other water sports. The perfect crew member for any sailing trip, the Radio-controlled, solar powered Sea-Pathfinder. SPW-1000 is multi-region which allows you to switch between transmitters in UK, USA, Japan and most of mainland Europe. That's not all, underwater depth measurement down to 30m, Thermometer, Barometer, Yacht Timer and many more features.

Key Features: Water resistant 100m; Solar power; Time Calibration Signals; Digital compass; Barometer; Thermometer; Depth gauge; Low temperature resistant; World time; Countdown timer; 1/100 sec stopwatch; 5 Daily alarms; Electro-luminescent backlight; Duplex LC Display.

Price: £199.99
There are also cheaper versions with slightly different functionality available in this range.