2 types of display mode available. (Time display only, Time/Date/Temperature rotation display) Calendar, Alarm, Temperature (℃ or ℉, Range: 16℉~122℉), 12/24H time mode, 3 levels bright (High->Medium->Low->Off) Automatic brightness control function using the light sensor is a mode in which the LED is set to the low brightness in the dark space without light and the LED is automatically changed to the high brightness in the bright space. Please note that this item is powered by adapter only. The built-in CR2032 battery is for time memory feature only and is not a power source. Size: 8.46 x 0.87 x 2.95 inch (W x D x H)