Long setting countdown time: 999 days, 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-hour and 24-hour format options. Easy to set. Two placement options: magnetic back and adjustable stand. Suitable for various occasions such as vacations, weddings, baby arrivals, retirement, meetings, and studying. To set the clock: Press and hold the CLOCK button until the hour starts flashing. Use the UP/START or DOWN button to adjust the value. Press CLOCK repeatedly to set minutes and seconds. Press CLOCK again to confirm. In clock mode, press the DOWN button to switch between 12-hour and 24-hour formats. To set the countdown time: Press and hold the SET button until a number starts flashing. Press SET repeatedly to select the digit to change. Use UP/START or DOWN to adjust the selected digit. Holding UP/START or DOWN changes the number quickly. Continue pressing SET 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. Size: Approximately 15.5 x 5.7 x 1.1 cm. Package Contents: 1 x Digital timer clock. Other items not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowance is +/- 1-3 cm.