Like diving, diving flashlight must be no stranger. Diving flashlight is a necessary diving tool, the market for all kinds of brands so that everyone is overwhelmed, no choice. When we choose diving flashlight, we can choose our own style from the following aspects.

1. Brightness
   Diving flashlight can first look at the brightness. A measure of a flashlight’s brightness is a lumen, a physical unit that describes the flux of light. And brightness is divided into concentrating illumination and astigmatism illumination. We choose the brightness of diving light, to consider the diving time, location, environment, depth, purpose, and technology.
   For novice divers, 700-1000 lumens is an option to meet the basic needs of daily diving. For more difficult night dives, deep dives, cave dives, etc., the brightness of the dive lamp is higher. Dive lights of 2000-5000 lumens are optional. For the brightness up to 5000-10000 lumen diving lights, higher brightness, can be used for outdoor activities, night travel, travel, rescue and disaster relief.
   The use of concentrating light and astigmatism is different, concentrating light can be used for long-range lighting, astigmatism is suitable for close range lighting. Wide range of lighting, can be used for photography.

                                   
2, waterproof
   Waterproof is the first guarantee of diving products, diving light if there is no waterproof, or water resistance is not good, can not play a normal function. The waterproof of diving light depends on the sealing and switch structure of diving light. Most submersible lights are made with silicone rubber rings, although they are also waterproof. But the elastic repair ability of the silicone rubber ring is poor, easy to be affected by high and low temperature, acid and alkali corrosion resistance is poor, if not replaced in time, for a long time, the sealing effect of the diving lamp becomes worse, it will slowly seep water.

3. Switch
   There are two kinds of switch, the first is the common “magnetic switch”. Magnetic switch is the use of magnets, using its magnetism to change the size of the current, to achieve the purpose of on or off.
   However, the instability of the magnet is poor, and the corrosion resistance is low. Under the erosion of seawater for a long time, the magnetism will be weakened, and the sensitivity of the switch will be reduced accordingly.
   Magnetic switch pay special attention to prevent switch salt, sand or foreign matter, to avoid the switch can not move, resulting in switch failure. And the earth itself has a magnetic field, the magnetic field will also bring certain interference to the magnetic switch!
   The second is the use of thimble type mechanical switch. This kind of switch uses the button operation, safe, sensitive, stable, strong directivity. The conversion can be operated even at high pressure in deep water. It’s great for taking pictures.

4. Battery life
   The last thing we need to focus on is the endurance of the diving lights. When we buy a flashlight, we should look at the use of battery and endurance. At the same time, the electric indicator light of diving flashlight can provide us with good instructions. Generally, the longer the endurance time, the longer the diving time, the more can ensure the safety and lighting underwater. The battery life is usually three to five hours.

   And brightness is inversely proportional to battery life. As long as we master these points, we can choose the right flashlight for ourselves.