PURSUN PS-220 Digital Countdown Days Timer - Black/White Upgraded Big 999 Days Count Down Clock for Vacation Retirement Wedding ✔️Upgraded version: Bigger size & Count-up function. Product size: 15.5 * 5.7 * 1.1cm / 6. 1*2.2*0.4in. LCD screen size: 13.8*4cm / 5.4*1.6in. ✔️Long setting time (Count Up & Down): 999 days, 23 hours, 59 minutes and 59 seconds. ✔️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. ✔️Requires: 2 * CR2032 battery. (Batteries are Included.)Wide application: vocation, wedding, new baby, retirement, meeting, study, and so on. How to Set Counting-up?If it is timing, press the UP/START button to stop it.Press and hold the UP/START and DOWN buttons at the same time to reset to 0.Press the UP/START button to start the counting-up. 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.Keep hitting SET until the screen stops flashing. Press the UP/START button to start or pause the counting down. -- You can choose 12 or 24-hour systems.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.