Usage: Press the S button to set the second display position, press the M button to set the minute display position, press the START / STOP button to start or stop, and at the same time press the MS- Button to reset the display to zero. An alarm occurs when the set time counts down to zero seconds. Function: Countdown function, can count down up to 99 minutes 59 seconds, automatically return to the set countdown time when the countdown is complete; Counting function, press the M and S buttons at the same time to reset, then press the START button to start counting. Product attributes: Outside size: 7 * 8 cm, window size (LCD): 6.3 * 3.8cm with a conventional AAA battery (This product does not have a battery, you need to buy it by yourself). Small and Portable: There are magnets and brackets, free hanging holes on the back; it can be attached to a metal surface, placed on a table, or hung; There is a foldable hanging hole above the clip that is suitable for hanging on a nail. Large screen: Large numbers are clearly displayed, three-button design, simple and convenient operation and setting. The back of the product has a rear clip that can be clipped onto the belt.