Bowhunter requested some measurements, so… I’ve got some more pics with measurements. 
Enjoy.
Viktor
VIKTORI
THANKS SO MUCH FOR TAKING THE TIME TO DO THE MEASUREMENTS ON THE LENS AND PILL!!!
GREAT JOB!!
Quick Question - what size O-rings have you had luck with? Regards, Bob (KumaBear)
Heh, none, actually.
That yellow “oring” is actually a plain old rubber band, used for closing up nylon bags you put in the freezer, or something similar. I found it in a kitchen drawer among 200 assorted other bands like that. :-/ And that was after I went to the store and bought a too “fat” oring of the proper diameter. Clearance between head and body is really minimal, so with my store bought oring the head would not slip over it. 
Viktor
viktor, thanks for the photos, measures, review in general. Yesterday came to my hands that torch, the bezel in M12 is 41 mm , but the lens is 30 effective mm ¡¡.
What do you think about lens? is possible to change to another bigger? ,yes I think we have to change the zoom path to have a nice spot.
It´s a pity to have this small lens and the body too big.
In my keygos m12 the o-ring envolving xml came totally off center , ¡¡
In high mode, I have to put thermal paste in threads because get too warm in few minutes.
I have no time to disasembling the whole torch , this weekend I will do.
Has anyone checked tailcap readings?? Is it underdriven?
What’s the best driver for this light? NANJG 105C or this one with ramping?
Got my M12 today, tailcap reading is 1.8A on high, and yes I have DIY leads, very thick copper ones, so values are correct.
Will replace my drivers as soon as i can! Probably for a 8*7135
oooh thanks… i always wants to know how to disassemble my zoomies…
Looks like a lens from a t20 should fit, at least with some filing or lathe work. That would give t20 performance with this much nicer looking and feeling shape and 26650 battery space. The t20 lens has about the same flange diameter and around 5 mm. more active diameter.
The is also a Dx lens that might fit, though it is not as good. A Yezl t9 lens would probably fit and would give more throw and flood, though a smaller spot.
So Keygos is not the manufacturer but a store that put its name on the ones it sold.