When choosing a diving flashlight, many people would be confused about what the main concerns to be considered. The salesman shows you a number of advantages, but in fact, these are just the basic functions of a diving flashlight. It is a must-have tool for diving, so we should pay attention to avoid the following major mistakes.

Brightness

This question varies. The depth, the purpose, and the technique are factors concerned in choosing the brightness of a diving flashlight. And the flashlight brightness concentrates the illumination and astigmatism.

In general, 700-1000 lumens flashlight can meet the basic diving needs for the entry-level. if it is night dive, deep dive, hole dive, etc., Higher brightness is needing if it is for the night-dive, deep-dive, hole-dive, etc., 2000-5000 lumens is a perfect choice.  

More enthusiasts are fond of 5000-10000 lumens, which is high-end demand, very bright, for any purpose.

In addition, even for the same lumens, the purpose of concentrating and astigmatism is completely different. Concentrating is mostly used for long-range illumination, while astigmatism for photo photography, close-range, wide-range illumination.

2. Waterproofness

Waterproofness is the first concern for a diving light. The waterproofness of diving lights mainly refers to the sealing and switch structure. Ordinary silicone rubber rings are the basic choice of the diving lights on the market. If not replaced timely, it would lose its sealing effect, causing water seepage.

3. Switch

The magnetic control switch takes advantages of its magnetism to change the magnitude of the electric current, to be on or off. However, the magnet is not stable steadily, which is eroded by seawater easily once it touches the saltwater for a long time. In that condition, the magnetism is slowly weakened and the sensitivity reduced. 

The Earth itself is a large magnet that generates a magnetic field that would affect magnet switch function.

4. Battery run-time

For night diving, it needs to turn on the light before jumping into the water, so the battery life less than one hour is not enough. 

When making a choice of a diving flashlight, you should not only focus on brightness but the battery life. If it is a 18650 lithium battery, with 1500-2000 lumens, indicating to be used for 2 hours, there is an absolute error. There must be a mistake in brightness and battery life.

Tips: (From Migual who is a professional diver)

after each dive，must be rinsed it with fresh water and left to dry

2. The battery charge lasts approximately 3 days between 4 to 6 dives, depending on the bottom time of each dive. 

3. Every time the battery is changed, must check the condition of the o-rings and that they do not have any sand, dirt or damage, if they are clean and in perfect condition, with slightly wet fingers of silicone grease, we lubricate the O-rings and both sides of the thread and we screw again and the flashlight will be ready for the next dives.