Long setting countdown time: 999 hours, 23 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. Switch between 12-hour and 24-hour format. Easy to set and operate. Two placement options: magnetic back and adjustable bracket. 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 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 format. How to set countdown time: Hold the SET button until a number starts flashing. Press SET to select the digit to change. Use UP/START or DOWN to adjust the selected number. Continue pressing SET until the screen stops flashing. Press UP/START to begin or pause the countdown. Press and hold UP/START and DOWN buttons simultaneously to reset to zero. 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 Note: Light and display differences may cause slight color variation between the image and the actual item. Measurement error allowed is +/- 1-3 cm.