Long setting countdown time: 999 days, 23 hours, 59 minutes and 59 seconds. Upgraded version with larger size. LCD screen size: 13.8 cm x 4 cm / 5.4 x 1.6 in. Alarm sounds for sixty seconds when the set time is reached. Includes clock function with 12-hour and 24-hour format switching. Easy to set and operate. Two placement options: magnetic back and adjustable stand. Wide application for vacation, wedding, new baby, retirement, meeting, study, and more. How to set the clock: Hold the CLOCK button until the hour starts flashing. Press UP/START or DOWN to adjust the hour. Press CLOCK repeatedly to set minutes and seconds. Press CLOCK again to confirm and start. In clock mode, press the DOWN button to switch between 12-hour and 24-hour formats. How to set countdown time: Hold the SET button until a number starts flashing. Press SET repeatedly to navigate to the digit you want to change. Use UP/START or DOWN to adjust the selected number. Hold the button for faster adjustment. Continue pressing SET until the display stops flashing. Press UP/START to begin or pause the countdown. To reset to zero, press and hold both UP/START and DOWN buttons simultaneously. Requires 2 x CR2032 batteries (included). Color: black Material: ABS Size: approximately 15.5 x 5.7 x 1.1 cm Package Contents: 1 x Digital clock (Only the above items included; other items not included) Note: Lighting and monitor differences may cause slight color variations between the image and the actual item. Measurement tolerance: +/- 1-3 cm.