Monitors inside temperature in degrees Fahrenheit and Celsius. Atomic time and date with optional manual setting. Automatically updates for daylight saving time (on/off option). 12/24 hour time. Perpetual calendar. US time zone selection: Eastern, Central, Mountain, and Pacific. Time alarm with snooze. Wall hanging or free standing. Indoor temperature range: 14.2 F to 139.8 F (-9.9 C to 59.9 C). Requires 2 AA alkaline batteries (not included).