Wurkkos WK20S - Dive Light with XHP35 and 18650

Disclaimer: I was kindly offered the Wurkkos WK20S flashlight for review. Amazon link (non-aff)



General Info:
The Wurkkos WK20S is a new diving flashlight, powered by a 18650 battery. Unlike the Sofirn SD05 dive light that I recently reviewed that uses a magnetic twist ring, the Wurkkos WK20S uses a magnetic push-button switch. The WK20S features a XHP35 HD (domed) LED with approximately 5300 CCT, nicely centered in an orange peel reflector.



Fit & Finish:
The quality of the WK20S seems great. The anodizing is has a nice, satin feel to it. It has a good solid heft to it. The threads are square and smooth. The bezel on mine is not glued on, though the tube appears to be glued to the head. The switch has quite a bit of travel. The tailcap has double o-rings for a tight seal when diving. The head has at least 3 o-rings: at the lens cover threads and both sides of the glass, which is quite thick, just like the SD05.



Runtime:
A nice, flat regulated runtime which is to be expected of a good boost driver. The light ran for 150 minutes before eventually shutting off with a measured battery voltage at 3.03V (seems a bit high, but not too bad). With the mass of the light and the timed (?) stepdown, the light doesn’t really get too hot. The output dropped from Turbo (~2000 lumens) to High (~1000 lumens) at 2 minutes. That seems awfully fast to me. But on the plus side, it maintained High mode for nearly 80 minutes.





Operation:
The UI of the WK20S is about as easy as it gets. There are four modes (Low, Medium, High, and Turbo) with apparently no Strobe or SOS functions. Press once to turn on, press again to rotate upward through the modes. Long-press to turn off, though the long-press is actually quite short. Once the battery runs down a bit, the WK20S actually just skips Turbo instead of quickly stepping down, which makes it appear to only have 3 modes. There is mode memory.



Misc Info:
This came packaged in a relatively nice cardboard box, and contained everything you’d need to run it: the flashlight, a Wurkkos-branded 3000mAh 18650 battery, a charger and USB cable (akin to the Xtar MC1), spare o-rings, lanyard, and instructions. Overall, a nice kit.



Here’s the WK20S with a brother and a cousin. Left to right: Wurkkos WK30, Wurkkos WK20S, and Sofirn SD05

I recently got emailed an offer of a free dive light from these folks if I would review it.
I replied that, not being a diver, I could not give it a proper pressure test
and I would not trust a recommendation on a life safety critical item that wasn’t properly tested.

They replied they had tested the light but were having trouble getting noticed.

I’m going to look up some SCUBA diving sites/magazines and suggest they get real divers to try them out.

I’m eagerly waiting for some company to offer me a free parachute or rock climbing gear if I’ll try them out and post reviews ….

Thanks for the review :+1:. Looks like its the same body as the Sofirn SD02 I had which was very well made. A nice improvement on the led and driver (SD02 had no regulation). Thermal (not timed) stepdown could have been a better solution, especially for a dive light. Also like many here, not a fan of the hold to off UI. I replaced leds to SST20 FA2s in my SD02. Took it wet caving once and one of the local guides wanted it so much so I sold it to him for very cheap. It did get submerged a lot with no problems but was not able to test it diving. Looks like nitecore 40mm filters will also fit so this could also be a good option red/blue diving light.

I turned down their offer… 60 lumen low wasn’t going to get a good review from me.

Hank, I agree to a point. Unfortunately I was unable to test the dive-worthiness of this light. On the SD05 I was able to test it at 25 feet for hours with no ill effects, thanks to a well timed fishing trip. As such, I’ve made no claims or endorsements in those regards. But unlike a parachute or rock climbing gear, a diving flashlight can readily be used by a non-diver. I’ve tested what I could… things like UI, output, and runtime. And those are valid and objective whether or not an individual chooses to use this light under water.

Received a Wurkkos WK20S today. A really good sized diving torch to tackle all adverse weather conditions while hunting, camping, white water rafting, and so many other foul weather adventures. Could be a one-and-done light for some people.

This seems nice, but… am I the only confused about why there are so many diving lights coming out recently?

Maybe diving lights will become the All-weather, all-conditions tire of the flashlight world. LOL, but seriously, I think diving lights like the Wurkkos’ are really practical. Great amount of light output, very simple UI’s, and no worries about dropping it into deep water for prolong amount of time. Things happen, and diving lights are ready for it. My two-cents.

On the up-side, if the parachute doesn’t work, the company wouldn’t have to worry about a negative review.

That’s why I originally got my DV-S9 æons ago. Waterproof light, essentially sealed especially at the weakest point (switch), so it could work in the rain, on the ocean, in mud, anywhere, and not have to worry about water ingress.

I don’t dive, but a good soak in a utility sink filled with water was a good test (to me).

First post on BLF and long time lurker. I am an island inhabitant and own a pair of Wurkkos (Sorfirn) WK20S for scuba dives and snorkels. These lights are now a year and half old and have been taken to a depth of 40m around dive sites in the Ryukyu Islands Chain. They probably see 20-30 ocean outings a year.

The WK20S is a well designed and rather tough light. These things get banged up on boats and rocks/reef all the time, I haven’t ever had one fail to illuminate when I pressed the power switch. That said, it does has caveats: long press to turn off takes a bit learning and the 2000lm setting only works in a narrow range of a topped off battery (>4.0V).

But the worst caveat is the switch getting corroded despite diligently soaking all my gear in fresh water after dives and it may be due to me not immediately sumberging it straight after a dive. The switch does get sticky if not cleaned out from time to time. The spring is not stainless steel and the ferrite magnet is not coated or embedded within the push plunger portion of the switch. Thankfully, the switch is dead simple to maintain. I have included some photos of the switch disassembly. A pair of robust pointy tweezers are all that are necessary to remove the retaining ring; there are 4 little drain holes near the plunger port that can be used as a place to stick the tips of the tweezers, the retaining ring just screws out revealing the spring and plunger.

Never bothered to look, as I don’t go diving. Looks easy to “fix”, though.

Coating for the magnet (primer/paint, nail-polish, conformal coating like acrylic, etc.), and a plastic spring in the right size.

Hmm, good to know. Those seen like simple things that could/should be addressed at the factory but it’s a good thing it’s not too hard to maintain. I wonder how hard it would be to coat the magnet (nail polish sounds like a decent plan, LB) and find a suitable stainless spring? I get a boatload of results when searching Amazon for some.

Great first post BTW!

If you can clean and thoroughly coat the parts, (I think nail polish might work OK), THEN pack the cavity with scuba grease. Should help a lot.
I’ve got a few cheap dive lights and after rusting out the switch, I now take them apart and pack with silicone grease before they are even immersed.

Rinsing, immediate and prolonged rinsing like overnight and in warm water, will help but is not the total answer since saltwater will easily get inside, but be quite hard to effectively remove. Pump the switch occasionally while soaking.