“Great not-so-little diving light!”
Being a fan of Wurkkos lights like the WK20 and WK30, I gave the DL40 diving light a shot. I like diving lights because they’re pretty much guaranteed to be waterproof in case of rain, getting dropped into a pool, etc., whereas other “waterproof” lights might merely be water-resistant. This is a big light, a nice solid big light! It takes a pair of 26650s for lots (and lots and lots…) of runtime. Each cell is rated 5000mAH, which is spot-on in agreement with what my Opus says. Plus, the extra heft makes it shed heat quite well and not turn into a curling-iron if you leave it on turbo for too long. Underwater (as in diving), you’re talking about quite many gallons of active cooling.
DL40 in profile.
That said, the box that arrived was a nice locking-lid cardboard box lined with white foam. Inside were the light with cells inside, lanyard, 2-bay charger and usb cable, extra O-rings, and adapter-tubes in case you want to use 18650s in a pinch, as well as a multi-language user guide. You’re pretty much good to go at that point.
DL40 shipping box, just opened (top), and with goodies taken out (bottom).
First impressions are quite good. As usual, machining and finish are flawless. No sharp corners, edges, or points anywhere. Anodisation is a flawless semigloss black. Unlike other Sofirn/Wurkkos diving lights with smooth battery-tubes, the DL40 has large rectangular “treads” for extra grip. Given the thick lanyard rope with rubber sleeve, you’re not likely to lose your grip on the light, but the treads are there anyway. There’s a nice wide slot in the tailcap for the lanyard, ’though you’ll need some tool to help you along in pushing it through (toothpick to push, thread/wire to pull, etc.).
Four LH351D LEDs provide the light output, a nice neutral 5000K of creamy white goodness, the same LED that powers the WK30 and similar lights. Each LED in its own reflector will show a somewhat “flower-petal” pattern in the outer beam (spill), but the hotspot is perfectly circular. There’s a slight yellowish tinge in the corona, but it’s not objectionable, and in fact not even that noticeable except if you go white-wall hunting.
DL40 head, showing the 4 reflector-wells.
It has 4 levels, low/medium/high/turbo. The manual says they’re 300/820/2000/5000lm, respectively, and I have no reason to doubt it. Turbo lights up the room via ceiling-bounce like the room-lights and then some. Instead of a much-hated timed step-down as many lights have, the DL40 has on-board temperature regulation which only steps down the current to the LEDs if the sensed temperature is too hot.
The user-interface is simplicity itself: click on, click some more to cycle through the modes, click’n’hold to turn off. No blinkies, no secret modes, no fluff, just simplicity. Mode-memory means that the next time you turn it on, it’ll be in the same mode as what it was in when you last turned it off. If you’re underwater, you certainly don’t want to strobe yourself or anything, so this UI is perfect.
The pushbutton magnetic switch is not a through-hole, so there’s no chance of seawater or any water getting in through there. The tailcap and head both connect to the battery-tube with dual O-rings, each, so there’s little chance of water getting into the light that way. If the front bezel is removable at all, I haven’t been able to do it, so I’ll take it on faith that it’s adequately sealed. 
The light can be “locked out” by giving the tailcap a half-turn unscrewing, to keep parasitic drain from depleting the cells. That might take a year or two, but if you leave the light unattended for long periods (over the winter?), it’s a good habit to get into anyway.
Charging the cells initially via the included charger is a breeze, too. Pop in the cells, connect to a USB charger or even just a computer port, and let it go. The lights will indicate red while charging, green when done.
Charger, while still charging (red, top) and when finished (green, bottom).
Negatives? Can’t think of any. Slight battery-rattle if you shake the light really hard, that’s it, but it is a 2-cell light, so…
So, unlike a lot of diving lights with only one cell and limited runtime, the DL40 should keep going, and going, and going, with a pair of beefy 26650s powering it. It’s a nice big light with a good grip, that’s not limited to diving. Anywhere you’d need a light to be absolutely waterproof, the DL40 is a great option to have. Me likey! :laughing:
DL40 on its box (top), and compared in size to an SP10 (bottom).
. like on a Convoy C8+ for example. Otherwise typical Sofirn high quality feel and look.
