With loud alarm ( , the beep sound differs per channel). It will start to count up when of the countdown time is reached. So you will know how long it has passed. It is useful when you are cooking. OCCASION -- cooking, classroom, laboratory, fitness, beauty, children eating, sports, meeting,etc. The maximum setting time is: 99 hours 59 minutes 59 seconds.Each timer has own unique sound so you can tell which one is going off. Product Name: Digital Count Up Down Timer 3 Modes: clock + countdown timer + stopwatch 4 channel countdown timer.The 4 sets of give you some flexibility. It can be used at the same time when baking several different batches of something. It starts to count up at of your set countdown. to place the timer: Stand / Magnet / Hang. You can attach it on your fridge; Stand it up on your kitchen counter; or hang it . and clear digits display. Clock Mode: Press CLOCK button for about 2 seconds until the time starts to flash. Press "" button to set "hour", "MIN" to set "", and "SEC" to set "second". Press CLOCK button to exit the setting screen. Countdown Timer Mode: Press a timer button (T1-T4) to select a timer. Press to set "hour", MIN to set "", and SEC to set "second". Holding down any button (/MIN/SEC) to increase setting at high speed. Press START/STOP to start/pause the timer. Stopwatch Mode: When the timer setting is zero,press START/STOP,timer will start to count up. Press the START/STOP to start or pause Stopwatch. Timer Weight: 86.3g / 3.04oz Requires: 2 x AAA batteriesNot included colour:White, gray Material:plastic size:848435mm LCD Size: 54mm * 23mm (2.13*0.91 in) Package Contents: 1x Digital Countdown Timer Note: Press CLEAR to clear the timer setting to all zeros. The continues for one or press the START/STOP button. Each timer has own unique sound. It will start to count up when the setting time is reached. 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.