Countdown duration: 999 days, 23 hours, 59 minutes and 59 seconds. LCD screen size: 13.8cmx4cm/5.4x1.6in. Alarm duration: sixty seconds upon reaching the set count. Clock function: Switchable between 12 and 24 hour systems. Mounting options: Magnetic back and movable bracket. Applications: vacation, wedding, new baby, retirement, meeting, study. How to set clock: Hold the CLOCK button until the clock number "hour" starts flashing. Press UP/START or DOWN to adjust that particular number. Keep pressing CLOCK to set minutes and seconds. Press CLOCK again to start. In the CLOCK mode, press the DOWN button to switch between 12 and 24 hour systems. How to set countdown time: Hold the SET button until a number starts flashing. Press the SET button until you reach the number you want to change. Press UP/START or DOWN to adjust that particular number. Hold UP/START or DOWN to change the number quickly. Keep pressing SET until the screen stops flashing. Press the UP/START button to start or pause the countdown. Press and hold the UP/START and DOWN buttons at the same time to reset to 0. Requires: 2 x CR2032 batteries. Batteries included. Colour: black/white Material: ABS Size: approximately 15.5x5.7x1.1cm Package Contents: 1 * Digital timer clock Only the above package content, other products are not included. Note: Lighting conditions and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.