Sofirn SP40

Sofirn SP40 review, headlamp


Brand/modelSofirn SP40
CategoryBest headlamp
Lumens1200 lm
Beam intensity4520 cd
Battery config.1*18650


The Sofirn SP40 marks Sofirn’s entry into the headlamp arena, with a very familiar right-angle e-switch 18650 design. While there may be a lot of similar lights on the market, Sofirn has attempted to distinguish itself with the included accessories and a very aggressive price point. This could therefore be one of the best headlamps on a budget!

Equipped with a Cree XP-L HD and an OP reflector, this headlamp is designed for close-range work, and it does quite well at that.

This light was provided by Sofirn for review – I have not received any other form of compensation for writing this review, so I have attempted to be as balanced as possible.


The light was packaged well in a change from the Sofirn-branded packaging I’m used to – it came in a plain cardboard box. All components fit snugly with no noticeable movement within while handling; perhaps if I shook it hard it may have rattled, but picking it up and moving it, I didn’t discern any contents moving. The light itself was in a sleeve of bubble-wrap to preserve the finish. Inside the box was:

What you’ll get:

  • The SP40 itself
  • 18350 tube
  • Headband
  • Clip
  • Spare O-rings
  • Micro-USB cable
  • Manual
  • Small promotional material about the Sofirn Deals page on Facebook

Handling of the light and knurling

My initial thoughts on picking up the Sofirn SP40 were quite positive – it fits in my hand quite well, it’s neither excessively heavy or light, and the button protrudes just the right amount for easy activation. With a battery in, the weight centres more, and it feels very well balanced.

The headband fabric is very soft, and sits nicely on my head. Now, I don’t have the smallest head in the world (605mm/23.8” around where the strap will go), but the straps are at maximum length on my head, and it fits – there will be some out there who may have some issues with this, but I’d say that the number of people that will have issues with the headband will be quite small. The only other minor issue with the headband is that the loops that hold the light in are a *little* too tight, which makes getting the light in and out of the headband a little harder than one would expect, and rotating it in situ can be a little tough. Again, not enough of an issue for me to be annoyed by it, but worth mentioning nonetheless.

The clip included adds extra functionality by allowing the Sofirn SP40 to be mounted to a belt, bag strap, pocket, etc – quite useful for mounting the light lower than head height if needed. I would have loved a deeper-carry clip to adjust the weight balance downwards more, but that’s a very minor issue, and one that I feel most won’t worry about.

Tailstanding is, as expected with a flat base, perfect. No problems whatsoever.

Build Quality, threads O-rings and anodization

As with all the Sofirn lights I’ve used, the build quality is quite good. Sofirn has opted for a functional rather than elegant design, and in this case, it suits the light very well.

The anodisation of the Sofirn SP40 is consistent, and appears thick enough – while testing, I have connected and removed the clip multiple times, and haven’t noticed any particular wear other than small scuff marks which I’d expect; other lights I’ve attached a clip to have been a one-and-done deal – if you take it off, you’ll have some nice new lines for your light.

Heatsink fins on the rear of the head help to draw the heat away from the emitter, and while these are fine for the task, I think I would have liked to see more surface area – perhaps make the fins deeper, thinner, and add another one.

Knurling is present on the places you need it the most; the body and the tailcap. It’s grabby enough so as to be easy to unscrew when needed, but I didn’t notice any discomfort while doing so – no sharp edges here! An interesting note is the deeper tailcap, as this gives a little more knurling length to grab onto while taking the battery out. Some may feel that it could have been shortened, but it works well with the size of my hands.

The threads are square-cut and lightly lubricated; opening and closing the light is smooth with no hesitations. Mechanical lockout is a breeze with the threads and larger knurling patch.

The included clip is the standard Sofirn clip, which does the job well enough. I would have liked to see the inclusion or option of a deep-carry clip, but maybe that’s just me.

The tailcap doesn’t include a magnet – this would have been a nice addition, but not 100% necessary at this price point. The adventurous among you should be able to remove the tailcap spring and glue a 10×2 or 3mm magnet to the base, then put the spring back in, but I haven’t been able to try that myself by time of writing.

LEDs, Lens, Bezel and Reflector

The Sofirn SP40 comes with the Cree XP-L HD; the light I received is at 5300K, but it is also available in 3000K and 4000K. The downside of this is that for the tint snobs among us, there’s a noticeable green tinge to the light; this is probably far less noticeable when using outdoors vs white-wall hunting. The lights in the beamshot are as follows from left to right:

  • Lumintop FW3A with Nichia 219b sw45k
  • Sofirn SP40 XPL HD 5300K
  • Emisar D4 XPL HI 5000K

Sofirn have opted to use an OP reflector for this light – I feel that this was a good choice, as giving a wider hotspot is a better idea for a lot of the uses I can imagine for a headlamp.

For those who like to mod, the bezel is easy to open with snap-ring pliers, and uses a semi-standard 16mm MCPCB, so high-CRI options can be swapped in easily enough.


  • Length: 108mm
  • Head: 25mm (side to side) x 27.5 mm (front to back)
  • Body diameter: 22.5 mm
  • Tail diameter: 24 mm
  • Lens opening: 20.5 mm Weight empty: 59g / 2.08oz
  • Weight with Samsung 30Q: 104g / 3.67oz

Image 1: from left to right: Convoy S2+, Sofirn SP40

Image 2: from left to right: Convoy S2+, Sofirn SP40, Lumintop FW3A


User Interface:

The SP40’s driver has a UI that’s very close to the “Olight/Thrunite” UI – the only thing missing is a moonlight mode. To elaborate:

From OFF:

  • Single click: Last-used mode (memory)
  • Double click: Turbo

From ON:

  • Hold: Change mode (L/M/H)
  • Single click: Turn off
  • Double click: Turbo

This is my preferred UI when I don’t need anything fancy (ie. Anduril), but the lack of moonlight mode is somewhat disappointing. I’m hoping that Sofirn can revise this in later batches, as I feel it’s a very important addition for retaining night vision in dark areas.

Low voltage warning: LVP is built into the light.

Strobe/blinkies: If there’s a strobe available, I’m yet to find it. Not inherently a bad thing though; I’m happy for its exclusion.

Lock-out mode: Lockout mode is available by clicking four times from any mode; clicking four times again will unlock.

PWM: I was able to detect some PWM via phone camera, but I wasn’t able to detect any by eye.

Batteries and charging:

The Sofirn SP40 has an inbuilt Micro USB port for charging; as it uses a standard 18650, you can also remove it and charge it in a normal charger.

While the SP40 is available both with or without a battery, the kit I received was without. As the light only pulls slightly above 3A on turbo, nigh-on any battery will work in this light. I’ve tested this with both unprotected batteries (laptop pulls capable of ~6A) and a protected Wowtac battery – both appear to give off the same amount of light.

USB charge port


Amp measurement

Tailcap measurements were taken with a Fluke 87 DMM on a freshly charged Samsung 30Q. I noticed a very small amount of waver in current, but not so significant as to adjust the ratings I’ve written below.

  • Low: 0.03A
  • Med: 0.15A
  • High: 0.9A
  • Turbo: 3.2A


As seen in the graph, starting the light in turbo keeps it fairly bright for a little under 7 minutes, and then drops fairly rapidly to around 35-40% brightness. From there, it slowly dims over the next 3h53m, turning off when LVP kicks in. While the SP40 isn’t regulated, that’s a pretty big ask for something in this price range.

As I don’t (yet) have an integrating sphere/lux meter, the numbers below are from Sofirn’s documentation on the light. The lumen figures look close to accurate based on my knowledge of other lights; the throw numbers are ANSI – so realistically, half of that distance is where the “useable” limit is, in my opinion.


  • Low – 5 lm
  • Med – 90 lm
  • High – 450 lm
  • Turbo – 1200 lm


  • Low – 11m (29cd)
  • Med – 38m (357cd)
  • High – 85m (1800cd)
  • Turbo – 136m (4520cd)

Overall conclusion


  1. A LOT of headlamp for the price
  2. Super comfy headband
  3. Good range of included accessories
  4. LVP is nice to have (low voltage protection)


  1. No moonlight (<1lm) mode
  2. Some high CRI options might be nice
  3. XP-L HD’s tint (for the tint-snobs)

Author: Owen

Overall Rating: very good ★★★★★

There’s an awful lot to like about the SP40 – it’s right on the verge of being an incredible light, with only a few minor drawbacks. The price is fantastic for what you get, there’s USB charging onboard, the headband is very comfortable (more on that below),I don’t know how much I can reiterate – I’m a very big fan of the headband! I’ve had the Wowtac A2S for some time, and the rubber has always dug into my forehead at the ends of it, but the headband on the SP40 is just comfortable from the word go. I feel like I could wear this for hours and not be irritated by it, whereas I find myself wanting to take the A2S off within 10 minutes. Or maybe I’m just a little sensitive to that kind of thing…

There are a few things I’d love to see in future versions, but I do know that all of these additions come with a cost/benefit decision for Sofirn – higher CRI emitters, the change in UI to add moonlight mode, potentially USB-C charging instead of Micro USB – but I do understand that Sofirn has to build to target their largest markets.Even with those things in mind, I’m more than happy to give this light 4.5/5 – it’s a fantastic light, especially for the price, that will do what you expect of it, when you expect it.I hope to see more great headlamps from Sofirn in the future!

Sofirn SP40 for sale

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