Plug In Clock with Battery Memory: The clock is powered by plug in a outlet, come with 5V1A power adapter to connect. A backup battery (CR2032) is included for maintain the memory if power goes out so time/alarm don’t need to reset, the cell button battery doesn’t power the clock. Alarm and Auto DST Function: Alarm is easy to set with 3 working mode –ring at preset time at Mon-Fri , Mon-Sat or Mon-Sun. Daylight Saving Time Function, set the DST to “ON”, the time will forward 1 hour in Spring and backward 1 hour in Autumn every year automatically. Dimmer + Night Auto Dimmer: The brightness of display is available to set to 5 levels manually, the last one is being off. With the auto dimmer function, the clock will automatically dim at the period of time. The second dots can be set to blinks or solid. Digital Clock for Wall or Desktop: Come with 2 folding kickstands and hanger hole, the clock can be either mount on wall or stand on desk/tabletop. Another smart design for this clock is a barrel wheel inside of compartment on the back which to wrap the excess cord. Ideal for using in living rooms, bedrooms, warehouses, garages, gym etc. Large Clocks: Extra Large Digital Clock (Length:10.25” width: 6.25”), 4” big bold number display , time is easy to read from about 20 feet away. Time and date (stay 3 seconds each) cyclic display. 12 hour / 24 hour system switchable. Great choice for vision issues or nearsightedness person.