The REED SW700 Heat Stress Stopwatch utilizes both air temperature and relative humidity measurements to calculate heat index and dew point—useful for determining the “feels like” temperature, or human-perceived equivalent temperature. This stopwatch also features a 10 hour countdown timer, audible alarms as well as a silent operation option, 99 lap counter with 30 lap/split memory, and fastest/slowest/average lap recall. The SW700 also features an backlit LCD display, both solar and battery power options and an IPX4 water resistance rating. Includes batteries and lanyard.