Casio Protrek Tough Solar Triple Sensor PRG-270-6A WatchCasio Protrek Tough Solar Triple Sensor PRG 270 6A PRG270 6A Watch Triple Sensor Version 3 is an original, advanced CASIO technology. Each of these three sensors are just 5% of a standard sensors size and more than one can be packed in one single, much smaller module with higher capacities and are more energy efficient. This created an entirely new and compact PRO TREK that reads altitude, direction and atmospheric pressure faster, better and longer.