Easy Operation & Package: There are 5 buttons on the digital clock: TIME, ALARM, SNOOZE/LIGHT, UP(+), DST(-). The function corresponding to each button is very clear. It is very easy to set up and use. Compact size:5.5 inches*0.9 inches*2.2 inches. It includes clock, 1.5m data cable, manual. The AAA batteries and adapter are not included. USB Powered & Battery Powered: The sreen is always on when the alarm clock for bedroom is powered by USB cable. If the clock is powered by battery, it needs 3 pcs AAA batteries(Not included), and the screen into the power saving mode after 10s automatically rests, you need to manually press the key to light up. We recommend using the usb power supply. 3 Level Volume & Snooze : There are 3 levels volume: L01-L02-L03/50-70-90DB. We recommend using the sound of the L03 directly to avoid the alarm sound being too low. You can get 5 minutes of extra sleep by pressing the "SNOOZE/LIGHT" button when the alarm goes off. Press any other key, you can cancel the alarm, and the alarm will remind you again after 24 hours. 4 Levels brightness: The clock for heavy sleeper adults has 4 types of brightness: High-Medium-Low-Off. At night, if you feel the light is too bright to disturb your sleep, you can turn off the screen. Note: If the clock is powered by battery, the brightness can't be adjusted. 5.8-inch LED display: OQIMAX Bedsides clock has a 5.8 inch LED dispaly, offers clearly visible numbers, and easy to read even from afar. The clock has multifuntions: DST automatic daylight saving time, alarm clock, calendar, 12/24 hours, backlight, volume. The colon in the middle of the time doesn't flash.