Introducing Triple Sensor Version 3, advanced CASIO original technology that makes it possible to pack sensors that are 95% smaller than those of previous models into a totally new type of compact PRO TREK. Despite their smaller size, the new sensors in these models deliver higher reading accuracy and improved energy efficiency. These Triple Sensor models deliver altitude, barometric pressure, and direction readings that are more accurate than previous models, and a Barometric Pressure Tendency Alarm alerts the wearer to sudden changes in pressure readings.