The TRIPLETT HSW50-NIST Heat Stress Stopwatch with Certificate of Traceability to NIST is ideal for monitoring WBGT levels in hot environments for worker safety, sports, and outdoor activities. It features a 3-line clear display for stopwatch, time, and calendar, WBGT (Wet-Bulb Globe Temperature) monitoring with alert, 1/100-second stopwatch that measures up to 10 hours, Lap and Split Time Recording with fastest/slowest/average lap record tracking, and 2-interval countdown timer repeatable up to 999 times. Additional functions include Stroke Frequency Counter for pace tracking adjustable between 10 to 320 paces, settable daily alarm, and auto-off LCD display to save the battery. Water resistant for outdoor and sports use. Includes Lanyard, CR2450 battery and Certificate of Traceability to NIST.