Nice light (SP31)! I got mine yesterday, played with it a bit, and like it. If anyone’s interested, I posted this review on Amazon:
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I’m impressed. I received the light, a Sofirn SP31, in a rather low-key cardboard box, no ribbons or anything shiny, and expected a low-key light as well, I was quite wrong. 
It comes with an 18650 cell and charger, but I didn’t want to wait so used a known-charged cell and flicked it on. Quite a nice tint right out of the box. A nice perfect neutral white hotspot, slight yellow halo around it, and somewhat bluish-white spill. Anything I shined it on looked very nice, though, so the choice of emitter was spot-on. As I said, a nice perfect neutral-white.
It’s quite lightweight, not as heavy as, say, my Zanflare F1 or Convoy S2+. Whether good or bad is up to you. There’s less thermal mass to absorb/spread heat from the LED, but the lighter weight makes it easier to carry in a pocket (ie, slip it in and forget it’s there ’til you need it).
I’m not terribly fond of the mode-spacing, though. Instead of moonlight/low/medium/high, it seems like moonlight/kinda-high/high/really-high. Ie, the three upper modes are visually spaced rather closely together with a big jump from the lowest setting. Still, the highest (“turbo”?) setting is impressively bright. I lit up the whole backyard looking for a noise-making critter last night.
Indoors, an informal ceiling-bounce test lit up the whole room.
On its highest setting, the light gets very warm, very fast! This is a Good Thing™. It tells me that there’s an excellent thermal path from the LED to the case. You want to shed heat from the LED as quickly as possible to keep it from cooking itself. If it gets too warm, just switch it down one setting to medium.
Speaking of modes, there’s no annoying blinky mode anywhere in the single-click rotation, thank B’harni (pbuh!). In fact, the UI (user-interface) is rather unique, at least in my experience. Instead of the progression 1-2-3-4-1-2-3-4-1-2-3-4~~…, it goes 1-2-3-4-3-2-1-2-3-4-3-2-1~~…, ie, low to high, then down to low, then to high, etc. Interesting! I’m not quite sure if I like it better than the usual. It may take some getting used to and I’d grow to love it, or it may end up grating on me, I have no idea. It’s just “different”. Again, good or bad is up to you. It’s a rather bold decision to buck the usual trend, at any rate.
As for the blinkies, okay, I tried them. Strobe is, well, strobe. Annoying to anyone you shine it at, possibly epilepsy-inducing, but muggles seem to looooove strobes. Feh.
What was quite interesting was “bike mode”, though. I assumed most “bike mode” lights do like what I often see, just a slower strobe, maybe once per second, more to be-seen than to see. This, though, seems quite useful. It seems to be the light being constantly on in high mode, but a repeating set of bursts in “turbo” mode. So it’s actually used to illuminate what’s in front of you, but also has that flicker to warn drivers that you’re there. Okay, this is a useful blinky-mode. Thankfully, it’s well-hidden, along with strobe (doubleclick and long-press).
Accessories? Lanyard, spare O-rings, pocket clip, that’s it. No case/holster, “tactical ring”, other stuff. The kit I received did include a charger (with USB charging-cable), and battery, but given the choice, I’d do without that, as I have several (smart…ish) chargers already, and enough 18650s to last me through the Zombie Apocalypse™. Before I even turned it on, I removed the pocket clip, as they just in general annoy me. Personal preference…
[nb: it’s a standard pocket-clip, not deep-carry, so half the light would be sticking out of your pocket if you were to use it — LB]
All in all, it’s quite a nice light. It’s lightweight, “crazy bright” as described in the blurb
, has a nice feel to it, has a perfect tint, and if you just want a nice little light to slip into a pants-pocket and forget about, I don’t think you can go wrong with it.