Tried my protected Eagletac’s, they fit and work fine so it seems any buttontop will do. Btw: you’ll never find a 14500 for the price of ordering one in the light and that one will fit.
I have both lights and just looked at the threads side-by-side.
Both lights use diamond-cut standard threads. There are no square cut threads in either light.
Also, the hosts (ie the aluminum parts: head, bezel, body tube, and tailcap) are 100% identical. All parts including the threads are interchangeable between the two lights. This is not surprising since the SP10Pro is just an SP10v3 with a different driver and different name stenciled on the anodizing.
The threads on SP10 are what many call square cut.
To be precise, I don’t think they are actually square cut. It seems to be trapezoidal thread. Regardless, it is not triangular cut threads you see in many cheaply machined lights.
Edit: I cleaned the lube off and looked at it more closely. I think the threads of SP10 Pro are indeed square cut threads.
These are not square cut threads - photos above are not sufficient to really tell, though. They are trapezoidal threads with the crests maybe a little flatter/wider than some. Not all that different than what’s on the Convoy T2/T3 and many other lights.
It can be tricky to see these clearly sometimes especially if they are shiny from grease or have direct light on them. Mildly backlit against a light background and with a low power magnifier you can clearly see that they are not true square cut at all. But that’s fine…they’re well machined and finished, feel great and work very smoothly, cap goes back on effortlessly, which is what’s important.
Forgot to post back about the H10 cells. Not getting much more from them but the one of the four gives a little more oomph. With the clamp I got a max of 2.5A and that one cell gave 2.6A, if the meter can be trusted there.
Also received the green magnetic tailcap. Nicely done, magnet feels on the weaker side, probably just N35. It has a larger/wider spring in there compared to the stock eared tail cap. I tried to remove the magnet with a long acetone soak and couldn’t get it to budge so I’ll likely break it out…have some N52 1/2”x3/32” coming in the mail which should add a couple pounds of pull or more.
The threads are called “Acme” the design is stronger than std v-cut threads. Kudos to Sofirn for using an upgraded thread. Now, hopefully they’ll correct that dam blink at the top!
Hmm. Shirnask’s pic on the red light has threads that look slightly different from my green SP10 Pro…closer to Acme (which is not a true square cut…better in some ways, at least from a machining standpoint) but they do not look quite the same as the US made Acme threads I have on hand to compare with, for whatever that’s worth. Very similar to what’s on the Convoy M1, WildTrail WT3M, Wurkkos FC11, Sofirn IF22/22A, and most Rofis lights. Wonder if they changed things up, perhaps different machines or locations. At any rate…well done threads, one of the few that are a pleasure to use with good feel and fit and not too much spring pressure to overcome when you start it on.