Honeywell TS03 Temperature Sensor, White Indoor/outdoor temperature User-selectable degree celsius or degree farenheit Outdoor temperature range: lithium batteries:-38-degree farenheit to 158-degree farenheit (-38.8-degree celsius to 70-degree celsius) alkaline batteries:-4-degree farenheit to 158-degree farenheit (-20-degree celsius to 70-degree celsius) One transmission channel Transmission range of up to 100-feet (30-meters)