Usage Tips:Long setting countdown time: 999 , 23 hours, 59 minutes and 59 seconds. Upgraded version: bigger size. LCD screen size:13.8cmx4cm or 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 see the clock number "hour" start flashing. Press UP or 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 see a number start flashing. Push the SET button get to the number you want to change. Press UP or START or DOWN to adjust that particular number. or START or DOWN, the number will change quickly. Keep hitting SET until the screen stops flashing. Press the UP or START button to start or pause the counting down. Press and hold the UP or START and DOWN buttons at the same time to reset to 0. Requires: Internal 2 x CR2032 batteries (Included) Colour: black Material: ABS Size: about 15.5x5.7x1.1cm Package Contents: 1 x Digital timer clock Only the above package content, other products are not included. Note: Light 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.