Reptile One Digital Thermometer / Hygrometer. Easy to read LCD display, and comes with AG10 battery. Displays both temperature and humidity, and records the maximum and minimum temperature and humidity fluctuations. Can display temperature as either celsius (C) or fahrenheit (F). Indoor temperature measuring range: -50 degrees (C) to 70 degrees (C) / -58 degrees (F) to 158 degrees (F). Indoor humidity measuring range: 10% - 99% Accuracy: temperature +/- 1 degree  humidity +/- 5%