The simplest and the easiest is to check if there is/are battery/batteries inside the flashlight.
There might be a insulating sheet in the bottom of the battery if the battery is selling with the flashlight.
Make sure the insulating sheet is removed before turning the light ON.
Check the battery polarity (most often positive towards the head)
If it is a rechargeable battery, is it charged? Make sure your flashlight is capable for rechargeable batteries.
If you have properly install fresh batteries, the light is still not coming out. You might want to check if there is a problem with your switch. First of all, remove the tail cap and then place a metallic object on the battery, make sure the battery is pressed down properly and the metallic object proper contacts the flashlight.
If the metallic object brings the light back, that the problem should be on the tail cap switch. Take a closer inspection to your switch, make sure there is no any loosen in the tail switch. If there is an obvious loosen in the tail switch, use a tweezers or proper tools to tight it up as following:
Twist the retaining ring counter-clockwise to make sure it is tightly in place. And then try again to see if the problem is solved.
Clean the contacts of your flashlight
Use acholol to clean inside the head, spring(s), tube ends and threads.
Make sure all part contact tight
If every part is contacting tight and correctly, the steps will bring back the light.
If the light is not work functionally, please contact our service to get help.
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