This water resistant (IPX4) stopwatch features a 10 hour countdown timer and built-in calendar that displays day, month and date. The SW700 is battery and solar powered and has the ability to measure temperature, humidity, heat index and dew point. This stopwatch combines air temperature and relative humidity measurements in an attempt to determine the human-perceived equivalent temperature or "how hot it feels". Measures temperature and humidity, calculates heat index and dew point. Stopwatch/chronograph mode with 1/100 second resolution. Calendar mode displays day, month and date. 99 lap counter with 30 lap/split memory. Fastest/Slowest/Average lap recall. 10 hour countdown timer with audible beeper warning for the last 5 seconds. Programmable alarm. 12 or 24 hour clock operation. 48" nylon lanyard. Backlit LCD display. Silent operation option. Battery and solar powered. Measures temperature and humidity, and calculates heat index as well as dew point. Blue. 3. 6"H x 2. 65"W x 0. 9"D. Combines air temperature and relative humidity measurements to determine "how hot it feels". Calendar mode displays day, date and time. 10 hour countdown timer. Large backlit LCD display. Solar or battery operated. Heat index range of 70 to 122degree f (22 to 50degree C). Temperature range of 23 to 122degree f (-5 to 50degree C). Solar powered stopwatch measures temperature, humidity and calculates heat index and dew point.