Wurkkos WK20S - Dive Light with XHP35 and 18650

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gchart's picture
Last seen: 37 min 45 sec ago
Joined: 03/19/2016 - 11:57
Posts: 1953
Location: Central IL
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.

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.

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

hank's picture
Last seen: 2 hours 41 min ago
Joined: 09/04/2011 - 21:52
Posts: 8679
Location: Berkeley, California

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 ….

Last seen: 14 hours 21 min ago
Joined: 07/17/2018 - 07:53
Posts: 275
Location: Philippines

Thanks for the review :THUMBS-UP:. 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.

Scallywag's picture
Last seen: 19 hours 54 min ago
Joined: 01/11/2018 - 22:23
Posts: 853
Location: Ohio, United States

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

EDC Rotation: ZL SC62 | Jaxman E2L XP-G2 5A | Purple S2+ XPL-HI U6-3A | D4 w/ Luxeon V | RRT-01 
EagTac D25C Ti | DQG Slim AA Ti | UF-T1 by CRX | Olight S1 | Klarus Mini One Ti
L6 XHP70.2 P2 4000K FET+7135 | Jaxman M8 | MF02 | Jaxman Z1 CULNM1.TG | Blue S2+ w/ ML Special
In-progress: Supfire M6 3xXHP50.2 
Others: Nitecore EC23 | Nebo Twyst | Streamlight ProTac 1AA | TerraLux LightStar 100

gchart's picture
Last seen: 37 min 45 sec ago
Joined: 03/19/2016 - 11:57
Posts: 1953
Location: Central IL

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.