I just received the Jet-1 MK from the Gearbest $12 deal a few weeks ago and on opening the head found the O-ring to be broken. The supplied spare ring seems to be for the Jet μ (I could be mistaken, but it does seem like it’d have to stretch over the AA sized Jet-1).
Gonna ask GB to send me a replacement, but in the meantime, I also noticed this 
They are meant to be streched. It could be my eyes, but o-ring in zip lock looks just like broken one (in diameter).
Ah, alright. My bad, I assumed the broken one did so due to stretching too much. Thanks, shall just pop it on then.
I also received JET-1 MK with broken oring 
but mine packing is printed ok, doesn’t say “CCREE”.
BUMP
Anyone know of a replacement O-ring with slightly fatter OD to tighten up the head? Currently, it does tend to rotate in my pockets and turn on; I have to loosen it nearly 180 degrees to be sure it won’t do that. 
CCREE?! 
Is there any fake Jetbeam in the market?
There seems to be a misprint in these, there are others receiving this pack.
I’m interested in buying this for the price, but it has the same led of the Lumintop Tool I ordered so I was kind of trying to get other deals, but it is hard to find a good 1xAA under $20.
I don’t like seeing this o-rings arriving broken, it probably means there is a design problem or they are not choosing the right o-rings for these.
I’m looking for bad reviews and I can’t find any complaints about o-rings. Maybe someone with a Jetbeam that came in a package without the mispelling and hadn’t had their o-ring break could measure their supplied o-ring and compare with yours.
Gearbest is indeed offering a big discount but I don’t know if they have the fame of selling counterfeits. It could be a new trend.
I don’t think it’s counterfeit at all, everything else checks out. The positive plate/contact area is one of the nicest I’ve ever seen! But compared to the jet-II, this one’s screwing action is a little loose and feels insecure. The Jet-II is perfect with that but sucks without mode memory. And i do like 14500 over 16340.
No need for a fatter o-ring. Just wrap some teflon tape around the threads. This will tighten up the threads…Works like a charm. :+1:
Now why didn’t I think of that. Thanks for the awesome tip, Streamer!