Long setting countdown time: 999 days, 23 hours, 59 minutes and 59 seconds. Upgraded version: bigger size. LCD screen size: 13.8 cm x 4 cm / 5.4 x 1.6 in. It will alarm for sixty seconds when reaching the set time. With clock function. You can switch between 12-hour and 24-hour formats. Easy to set. Two placement options: magnetic back and adjustable stand. Wide application: vacation, wedding, New Year, 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 again to set minutes and seconds. Press CLOCK once more to confirm. 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 value. Hold the button to change quickly. Continue pressing SET until the display stops flashing. Press UP/START to start or pause the countdown. Press and hold UP/START and DOWN together to reset to zero. Requires: 2 x CR2032 batteries (included) Color: black/white Material: ABS Size: approximately 15.5 x 5.7 x 1.1 cm Package Contents: 1 x Digital timer clock Only the above items are included; other products are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowed is +/- 1-3 cm.