In this review I would like to present you the Wurkkos DL40 diving flashlight.
Disclaimer:: This flashlight has been provided by Wurkkos free of charge for the review.
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Purchase links (non-affiliate)
Wurkkos DL40 on Aliexpress , Wurkkos DL40 on Amazon IT , Wurkkos DL40 on Amazon DE , Wurkkos DL40 on Amazon US
Introduction
The Wurkkos DL40 is a diving flashlight with four LH351D 5000K 90 CRI. The smooth deep quad reflector offers a floody beam with some throw. With 5000 lumens it is among the brightest diving flashlights and one of the very few with high cri leds. I am not a diver but I imagine high cri to be astonishing underwater, just like it is on the land. The Wurkkos DL40 can be used not only as a diving flashlight but also as a normal flashlight with extra water resistance. The build quality of Wurkkos is high because their flashlights are manufactured by Sofirn.
What is included
- Wurkkos DL40
- Two Wurkkos 26650 5000mAh button top batteries
- USB Charger 2 slots
- Micro USB cable
- Manual
- Two 26650 to 18650 adapter sleeves
- Lanyard
- Spare o-rings
Specifications
Measurements
Tailcap current (ampere draw)
Low: 0.4A
Med: 0.9A
High: 2.3A
Turbo: 6.8A
Appearance
The quad SMO reflector with four well centered LH351D’s frontally, leds off and lighted.
In this picture the glass lens looks like it would have an AR-coating but I’m not sure. It is not visible in person and the description does not mention a coated glass lens.
The Wurkkos DL40 with the lanyard mounted
Square cut threads and double o-rings at both ends of the battery tube
Big, 1mm thick and gold-plated springs on driver and tailcap
Battery and charging
There are two button-top Wurkkos 26650 batteries with 5000mAh included. I recharged the cells from 3.5V and it gave me a bit more than 4000mAh so I would say the rated capacity is correct.
The included charger is a dual slot charger with USB connection. It is a no name charger but it is made solid with no apparent flaws. Two led indicators are red when charging and green when finished. A charging indicator with three or four leds to show the charging state would be useful here. With a charging rate of 1A per battery the batteries should be charged in about three hours if you use a plug with 5V 2A output.
Comparison
The Wurkkos DL40 compared to some famous Sofirn flashlights, from left to right: Wurkkos DL40, Sofirn BLF Q8, Sofirn C8F, Sofirn SD05
Wurkkos DL40 in comparison with two other 2x26650 flashlights, the Convoy L6 and the Sofirn SP70.
Beamshots
Control
Low
Med
High
Turbo
Animated
Here you can see the Wurkkos DL40 compared to another diving flashlight, the Sofirn SD05 and some other famous Sofirn flashlights. All beamshots were made on Turbo with the settings 2s F7.1 ISO500.
Wurkkos DL40 LH351D
Sofirn SD05 XHP50.2 CW
Sofirn BLF Q8 XPL HD
Sofirn C8F XPL HD
Sofirn SP70 XHP70.2 NW
Animated
Some whitewall beamshots
The beam has a cloverleaf-formed outer spill around the round inner spill. This beam form looks not ideal on white walls but it is typical for quad reflectors and not noticed outdoors.
From left to right: Wurkkos DL40 5000K, Sofirn SD05 6500K, Sofirn C8F ~5300K
The Sofirn SD05 CW is quite green, while the Wurkkos DL40 is more neutral and warmer and the Sofirn C8F is the rosiest.
Wurkkos DL40 5000K, Sofirn BLF Q8 5000K, Sofirn SP70 5000K
You can see that the Wurkkos DL40 is slightly greener than the other 5000K flashlights with 70 CRI.
Teardown and internals
As written in the manual, you shouldn’t disassemble your flashlight as it voids the warranty and it may damage your flashlight. I’m showing the teardown and internal parts here so that you don’t have to unscrew the flashlight yourself risking to ruin it. This applies especially to a diving flashlight because if you do not reassemble it correctly the watertightness may be affected.
I did not manage to get out the reflector as there seems to be a screw to hold it down. I had to use quite a bit of force with vice and pliers to get the bezel loose but after a half turn it went off easily. It is not glued but screwed very hard.
!!
Conclusion
I would consider the Wurkkos DL40 a perfect diving flashlight. It is built sturdy, has a 5000 lumen Turbo mode, two 5000mAh 26650 batteries for extended runtimes and last but not least neutral white, high cri leds. The beam is floody but it has a bright spot with quite a bit of throw. The flashlight is only 20cm long and thus rather compact for a 2x26650 flashlight. The side switch is magnetic to prevent water ingress and it does not have the usual click sound and feeling. A side switch is better for one-handed use in this case because the flashlight is longer and heavier than single cell flashlights and you would therefore need two hands to operate a magnetic control ring. The Wurkkos DL40 is well suited for underwater use with double o-rings at the front glass lens and the battery tube, a thick battery tube and a 3mm glass lens. It is a truly great flashlight also outside of the water.
What I like
- LH351D’s offer a neutral white beam with no noticeable color shifts
- 90 CRI leds for an excellent color rendering performance
- Balanced beam with flood and throw
- Double o-rings at head and tail, thick glass lens
- Thick battery tube with long, square cut threads
- Relatively compact for a 2x26650 flashlight
- Can be used with one hand only, the side switch is easy to reach
What could be improved
- The LH351D bin used is a bit green, but you will not notice it unless compared to other flashlights.
- The modes are not evenly spaced, the low modes should be further apart but maybe under water lower modes are not needed.
Thanks to everyone for reading my review. 
For any questions or suggestions please feel free to ask and comment below.
P.S.: If I manage to get to a lake I may add a video with a underwater test later.