D+ 1D+ 2D+ 3D+ 4.Alarm function,three alarms, with ""beep"" lasting for 1D+ 5.Time display 12-hour or 24D+ 6D+ 7.Powered by USB power supply cable or 3D+ 8D+ Brightness: 3D+ Input: DC 5v/500D+ Dimensions: 6.5cm x 6.3cm x 6.5cm(2.5in*2.2in*2.5D+ If LED display keeps ON and only powered by batteries, battery is easy to waste (Works around 3D+ 1D+ 1D+ 1D+