3 minutes, when you receive the watch, you will find that at night, when the watch luminous failure, or not bright enough, you can use a mobile phone flashlight or flash to shine for 3 minutes, you can also use an ordinary flashlight to shine on the dial for 3 minutes, there will be night light. If the watch is not luminous, it needs to be filled with light. You can use a mobile phone flashlight or flash for a while, you can also use an ordinary flashlight to illuminate the dial for a while, you can have a luminous effect. Or put it in a sunny place during the day to let the sun shine on the dial. The luminous watch emitted by the luminous powder is emitted by the luminous powder itself is not luminous, but the luminous powder has phosphorescent characteristics, in the sun or light irradiation can be activated, luminous watch stored in a dark place for a long time, will cause the watch luminous is not bright.