The clock features an illuminated color display with indoor and outdoor temperature, Intelli-Time clock and calendar, moon phase and alarm settings. Offers the convenience of USB charging with a maximum output of 1000mA (1A) for compatible smartphones. Intelli-Time clock automatically updates itself for Daylight Saving Time. The programmable alarm can be set for everyday use or weekdays only. The outdoor sensor features powerful wireless technology, weather-resistant design and an integrated hanger for easy mounting. Features a wireless (RF) range of up to 330 feet (100 meters). Alarm clock is powered by a 5V power adapter (included; recommended for optimal display color) or 3 AA alkaline batteries (optional; not included). Wireless sensor is powered by 2 AA alkaline or lithium batteries (not included). Lithium batteries recommended for use in outdoor sensor for temperatures below 4 degrees Fahrenheit (-20 degrees Celsius). It's more than accurate, it's AcuRite.