Long setting countdown time: 999 hours, 23 hours, 59 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 with 12/24-hour format switchable. 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: Press and hold the CLOCK button until the hour digits flash. Use the UP/START or DOWN button to adjust the hour. Press CLOCK again to cycle to 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: Press and hold the SET button until a number flashes. Continue pressing SET to navigate to the digit you wish to change. Use UP/START or DOWN to adjust the value. Press SET repeatedly until the display stops flashing. Press UP/START to begin or pause the countdown. To reset to zero, press and hold both UP/START and DOWN buttons simultaneously. Powered by 2 x CR2032 batteries (included). Color: Black. Material: ABS. Dimensions: Approximately 15.5 x 5.7 x 1.1 cm. Package contents: 1 x Digital timer clock. Only the items listed are included; other items are not part of the package. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement tolerance is +/- 1-3 cm.