Seiko Ultrak 830 30 Lap Memory Heat Stopwatch Meet the Seiko Ultrak 830-30 Lap Memory Heat Index Stopwatch, the first solar-powered, heat-index stopwatch. On top of precisely recording your running performance, this stopwatch also accurately calculates temperature, humidity, heat index, and dew point. Stopwatch mode features 30-lap, dual-split, recallable memory and measures up to 10 hours with 1/100 second precision. It also includes a presettable countdown timer with automatic repeat function. The display has two lines and can even be viewed in low-light conditions, thanks to its LED backlight. The Ultrak 830 is powered by two solar panels and includes a back-up lithium battery. It also displays time, a digital calendar and has an alarm. Water resistant. Five year warranty.