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 switchable 12-hour and 24-hour format. Easy to set and operate. Two placement options: magnetic back and adjustable stand. Wide application for vacation, wedding, baby, retirement, meeting, study, and more. How to set the clock: Hold the CLOCK button until the hour digits start flashing. Use UP/START or DOWN to adjust the hour. Press CLOCK again to move to minutes and then seconds. Press CLOCK once more to confirm and start. In clock mode, press DOWN to switch between 12-hour and 24-hour format. How to set countdown time: Hold the SET button until a number starts flashing. Press SET repeatedly to select the digit to change. Use UP/START or DOWN to adjust the value. Hold the button for faster changes. Continue pressing SET until flashing stops to save settings. 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: white Material: ABS Size: approximately 15.5 x 5.7 x 1.1 cm Package includes: 1 x Digital timer clock