The bold, easy-to-read LCD screen displays accurate, reliable temperature readings from -4 to 158° Fahrenheit. Weather resistant construction is perfect for outdoor use. A suction cup mounts the thermometer on the outside of a window, and the temperature is read from indoors. Dimensions: 3.3" H x 2" W x .75" D. Powered by L1154 cell battery (included). By AcuRite.