Inspired by those who challenge high altitudes, the G-Shock Riseman features a unique three-layer structured twin sensor to measure altitude and barometric pressure as well as temperature. Add in solar power and atomic timekeeping technology and you've got nonstop, self-adjusting performance that is the Riseman. Dozens of features including: HOURLY TIME SIGNAL; AUTO-CALENDAR (pre-programmed until the year 2099); 5 DAILY ALARMS (1 snooze); THERMOMETER; MODULE 3147; MEMORY: 20 RECORDS; ATOMIC TIMEKEEPING (US, UK, Germany, Japan, China); POWER-SAVING FUNCTION; COUNTDOWN TIMER; SHOCK-RESISTANT; BACKLIGHT (auto EL backlight with afterglow); WATER-RESISTANT (up to 200 meters); 12/24-HOUR FORMATS; ACCURACY (+/-15 seconds per month with no signal calibration); 29 TIME ZONES (33 cities, city code display, daylight savings on/off); WORLD TIME; BATTERY POWER INDICATOR; STOPWATCH (1/100 second); and ALTIMETER. Solar-powered. Battery runs 9 months on full charge (without further exposure to light).