SecurityIng 1800LM Diving Flashlight, 5 Modes Scuba Diving Flashlight, Magnetic Switch, Rechargeable, Waterproof to 100m, Ideal for Scuba Diving, Snorkeling, and Underwater Adventures

First, I am not a diver and I don't have the background to review this light from an experienced diver's perspective. I like dive flashlights because they are sturdy and simple to operate and bright and impervious to water. They are good general purpose outdoor flashlights so long as you don't mind their weight. They're great for walking through the woods or a dark campground, but they are definitely not EDC or tactical flashlights.This SecurityIng flashlight is equipped with a surprisingly good 21700 size Li-ion battery (a Panasonic NCR21700T), which has a higher capacity but is much less common than the usual 18650 batteries. It ships with a lanyard, a USB-C charging cable, 4 replacement o-rings, and a very brief user manual. Complete with battery and lanyard, the light weighs 229g (8.1 ounce). It appears to be very well constructed from thick and sturdy quality materials. It has 3 brightness levels (250, 800, and 1800 lumens) as well as strobe (very slow at 1 Hz) and SOS settings controlled by a magnetic rotary switch. Comparing it to other flashlights in the backyard, the claimed light outputs are entirely credible. The beam is narrow, with a small hotspot (15° is claimed and believable) and surrounded by wide and much dimmer spill. The beam quality is good, with no rings or dark spots, and I found it very pleasing.The battery can be charged by unscrewing the battery tube from the head of the flashlight to reveal a USB-C charging port and a tiny red/green LED that indicates charge status (the location of the charge port is not mentioned in the user manual or the listing). Or the tail cap can be unscrewed to remove the battery for separate charging. A pair of o-rings seal the light at both the tail cap and the light head.The flashlight feels good in the hand and the rotary switch operates easily. It can be stood on its tail cap very stably to point at the ceiling for general room illumination. I like this flashlight very much for general purpose applications and expect it would perform very well as a dive light.

I received the flashlight and it doesn’t work

As far as flashlights go, I have had many flashlights over the years and this one is up there with the best of them. I know this is a dive flashlight, but I do a lot of activities at night so I like to have flashlights and back-ups for my flashlights so I don't get stranded in the dark somewhere. The most I will ever use this in the water is snorkeling, which I do about once a year in the Florida Keys. Most days, you do not need a light for snorkeling.This light is really great. It seems made well and I like how there are no obvious water ingress points on the light. To get to the charger, remember that you have unscrew the bottom portion of the light to get to the USB C port. You can unscrew the other side as well to gain access to the battery. And let me tell you, this battery is huge!The only one downside I see is that the mode switch is pretty easy to rotate. I have a feeling that was made like this intentionally to make it easier to change while wearing gloves, but I am not. As it is, it is easy to rotate and doesn't provide much dampening when rotating it. Not a deal breaker, but just thought I should mention it.

The USB charging port for this waterproof flashlight is found on the threads of the lower/barrel portion of the flashlight.The head of the flashlight unscrews beneath the mode ring. Unscrew and remove the head (top portion) of the flashlight and the USB charging port will be exposed on the threads of the lower portion (barrel) of the flashlight.This information is not stated on the instructions. You need to figure it out on your own where to find the location of the charging port. Or realize that I just provided you with the answer! :)A USB recharging cord is provided with the flashlight, even though the cord is not mentioned on the instruction sheet as being one of the included accessories. Therefore, I suspect that it may have been an afterthought to include the recharging cord; hence, why the USB charging port isn’t shown, mentioned, or addressed at all on the instruction sheet. But since this is a waterproof flashlight, common sense would dictate that the charging port would be hidden, and not be exposed to water.This is a good flashlight and produces a good strong beam of light. The mode ring also offers a blinking feature and also a SOS flashing feature.The issue that I have with this flashlight is how easily the mode ring rotates. It’s too easy for the flashlight to be turned on. Be it in your pocket, a backpack, or wherever, if the ring gets bumped the mode ring can easily be turned, the light comes on, and the battery is prematurely drained. Then when you need the flashlight, the battery is already drained and dead; needing to be recharged. In this regard, I would say that the flashlight is not functionally sound. Hopefully this aspect of the flashlight will be addressed and improved upon. (And that the instruction sheet will be reprinted with a diagram indicating where the USB charging port is located.) Overall, this is a good flashlight!