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 options. Easy to set and operate. Two placement options: magnetic back and adjustable stand. Suitable for various occasions such as vacations, weddings, baby monitoring, retirement, meetings, and study sessions. How to set the clock: Hold the CLOCK button until the hour display starts flashing. Use the UP/START or DOWN button 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 the DOWN button to switch between 12-hour and 24-hour formats. How to set the countdown timer: Hold the SET button until a number begins to flash. Press SET repeatedly to cycle through the time units (days, hours, minutes, seconds). Use UP/START or DOWN to adjust the flashing number. Hold the button to change quickly. Continue pressing SET until the display stops flashing. Press UP/START to begin or pause the countdown. To reset the timer 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 timer clock