I like it also for this.
I bought a couple of these AP-15 headbands from Battery Juction for a better price than the Nitecore model.
I hear the perfect light for checking on babies is a gchart piggybacked MCU on a SP40. Hope all is well
I wouldn’t doubt it 
I’m currently putting two of my babies (well, toddlers) to sleep as we speak. Their nightlight? A custom Sofirn SC31. At first I just did an MCU swap. Then I went all out and designed a driver that uses a watch crystal to keep (extremely accurate) time. 10 hours on, 14 off. Ramping UI, e-switch LEDs as battery warning, etc. And with the MCU running at a super low clock rate, standby drain is like just a few uA.
Now that you mention it, I was going to disassemble my SP40 to peak at the PCB/MCU but my buddy still has it. Hmmm… I’m going to need that back!
Board is not public, it has a mistake I haven’t corrected… just did an air wire
I didn’t see gchart’s measurements and took my own:
~17.35mm where PCB sits
lens: 19.37 x 1.1mm glass, could probably fit up to 19.5-6mm max
9.07mm reflector+glass height
6.57mm reflector led opening
Guys, did anyone think about switching to a smooth reflector in this flashlight, and does it make sense to do this to increase the throwing distance?
Can anyone give some pointers on how to remove the bezel? Mine seems screwed in very tightly (glued perhaps?) and I might not be using the right tools for the job. The reviewers imply it is easy, without describing how they accomplished this feat.
I’ve always used “”snap ring pliers”:Amazon.com such as these:
I’ve not tried removing the SP40’s bezel though.
-Garry
I 3D printed a tool - here’s the model if you want it:
I don’t have DC-fix but I have sheets harvested from laptop screens that perform similarly. I might have to resort a sheet diffuse enough to erase the hotspot.
I think it’s time for me to invest in a pair or a set.
Thanks, I know little about 3D printing but there is one at a library near me…
I use something similar to garrybunk, but mine are just a small set of needlenose pliers. I’ve also seen some folks using a set of camera lens spanners found on AliExpress for like $10. They look pretty slick.
I tried 90º snap ring pliers on my SP40 and all it did was scratch up the bezel. 
Would have loved to swap in a TIR.
For traipsing through the woods though the beam is perfectly adequate. 4000K on the warm side, illuminates fallen oak leaves like nobody’s business.
Don’t mind not having moonlight mode. Low is just right for me.
Oh and since I avoid being outdoors in the rain and have a highly water resistant travel bag in which to store the flashlight, took the liberty of installing a magnetic micro USB adapter plug into the port. Makes charging a breeze.
Hi, I am very interested to know the solution. I plan to order a SP40 and to add a diffusion film under the glass. Not sure if this possible but is it OK to ask Sofirn to losen the bezel for you when you make the order?
@MoreLumens : I may end up to use the adhesive version of the diffusion film. But it’s just more elegant and more weather resistant if the film was placed under the glass. With the condition, of course, that is is humanly possible to unscrew the bezel.
Got it!
Just ran the lamp head under my blow dryer on its top two settings before applying the snap ring pliers to the bezel, loosened it right up.
Oh cool thanks. What are the “top two settings” ?
Heat and fan speed on the Conair 1875. Probably would have worked just as well on low speed, but I wore insulated gloves and threw caution to the wind. 
It is easy after using a rubber band for better grip. No need for special pliers or risk scratches.
More details here: DC-Fix Diffusion Film Sale - #362 by phouton
Hi,
I have just received a SP40.
Light seems in good condition but when I double click for turbo mode, the output seems to run well for a couple of seconds and then it starts to do intermittent flashes. When I try to turn it off, the button does not work so I have to unscrew the end cap.
Do I have a defect product? Did anyone run into this problem?
Thanks,
Emilio
is your battery any good?
I`v seen a few lights get a bit flaky on turbo when the batts are either low or can`t supply the current needed.