... in the socket of output aperture.3 Turn on the key to right ,the screen show 05:00-3. It ... at last ,when all the light shining . you can press the start, the laser begin to work.When the ... laser is ending , their will ring bell remind. Press again the start .5 Reset : when using it , ... if you need to stop working , you can press reset button , after the sound is end, the timer return ...