The Meade TM005X-M Wireless Thermo-Hygrometer is an easy-to-read and economical way to track temperature and humidity in your home or office. Featuring a jumbo display unit with one-inch tall digital numbers, this sleek silver and black unit can monitor up to three remote locations. The TM005X-M comes with one remote sensor, but two additional sensors can be purchased separately and added. With the main display unit measuring 4.33 by 4.86 by 1.08--inch ;W by H by D , and a display that includes comfort and trend indicators, you can place the TM005X-M on your desktop or hang it from a wall. With the remote sensor, you can track the temperatures of pools, hot tubs, spas, ponds, soil, and much more. The remote sensor has a transmission range of up to 100-feet. With the sensor powered by two AA lithium batteries, the unit has an outdoor temperature range of minus 38 to 158-Degree fahrenheit , and when the sensor is powered by two AA alkaline batteries, the range is minus 4 to 158-Degree fahrenheit . ;The two AA batteries required for the sensor, and the two AA batteries required for the main unit, are not included.