From Extech:
The RHM15 is a mini hydro-thermometer monitor which measures humidity and temperature and displays it simultaneously. The RHM15 has a built in memory which stores maximum and minimum readings. The RHM15 features a low battery indication and comes with a built in stand, user’s manual and LR44 battery.
Temperature: 14 to 140°F
Humidity: 10% to 99% RH