Honeywell TS33C Temperature and Humidity Sensor with LCD Wireless Honeywell sensor with LCD screen for indoor/outdoor temperatures and humidity levels; Celsius or Fahrenheit display Transmits data up to 100 feet to compatible, separately purchased base unit; with 3 user-select transmission channels Outdoor temp range of -38 to 158 degrees F with alkaline batteries, -4 to 158 degrees F with lithium batteries; humidity range of 25 to 90 percent Requires separate purchase of 2 AA batteries; install out of direct sunlight or rain Measures 2-2/5 inches wide by 1 inch deep by 4 inches high; limited 1-year warranty