Long setting countdown time: 999 days, 23 hours, 59 minutes and 59 seconds. Upgraded version: bigger size. LCD screen size:13.8cmx4cm/5.4x1.6in. It will alarm for sixty seconds when arriving at your setting number. With clock function. You can switch between 12 and 24 hours systems. Easy to set. Two ways to place it. With magnet back and movable bracket. Wide application: vocation, wedding, baby, retirement, meeting, study, and so on. How to set clock: Hold the CLOCK button until you see the clock number "hour" start flashing. Press UP/START or DOWN to adjust that particular number. Keep hitting CLOCK to set minutes - seconds. Press CLOCK again to start. In the CLOCK mode, press the DOWN button to switch between 12 and 24 hours systems. How to set countdown time: Hold the SET button until you see a number start flashing. Push the SET button until you get to the number you want to change. Press UP/START or DOWN to adjust that particular number. Hold UP/START or DOWN, the number will change quickly. Keep hitting SET until the screen stops flashing. Press the UP/START button to start or pause the counting down. Press and hold the UP/START and DOWN buttons at the same time to reset to 0. Requires: Internal 2 x CR2032 batteries (Included) Colour: white Material: ABS Size: about 15.5x5.7x1.1cm Package Contents: 4 x Digital timer clock