The HW30 is a multifunctional stopwatch that has a digital up/down timer, temperature, humidity, and heat index capabilities. The heat index measurement indicates how hot it feels when humidity is added to the actual temperature. Ideal for hot weather applications. A 12/24-hour clock, stopwatch, 30 lap/split memory, and programmable alarm round out the list of features. The HW30 Humidity/Temperature HeatWatch comes with a lanyard, battery, and operation instructions.