Compare my SF U2's

I now have both SF U2's I bought. The one with serial# A12900 has a rounded body, no flat sides. Now the one with serial# A04279 has two rounded sides and 2 FLAT sides. I was reading in the marketplace that someone wants to buy a flat sided U2 so they can use 18650 batteries. My flat sided one does not have a black sleeve in it, but since it has the flat sides does that mean it can accomodate the rechargeable 18650's? If so then I will use that U2 for the Milky mod. • • Also, do the newer round models have on the U2 clip the round plastic/rubber piece that says "SF" and above it has a rubber square piece I assume to hold the SF round piece in place? Picture below shows what I am talking about. Thanks for the help.

I've never seen the "rubber square piece" before. I don't see why it's needed.
I'm interested to learn whether it is supplied with U2's.

I bought it from MikeLip (forum member) and I got it the way he bought it, no alterations.

There's an old post which I was unable to trace with 'Search' in which a member showed a picture of the piece of rubber he put on the clip. The purpose was to avoid that the SF button moves upward. I remember this because I tried to do the same on my U2 but the result was poor and I dropped the idea.

I've never had the SF button even consider coming detached, I've got four SureFires that use this design.
I didn't even realise it was an issue to others...

My U2 has the 2 flat sides (with 2 rounded sides as well). It will hold a 18650 cells with no problems. You have to load it from the front, as it will not fit through the opening with the tailcap removed.

I believe the progression was:

2 flat sides, big enough bore for a 18650

2 flat sides, sleeve inserted to make it too small for 18650.

3 rounded sides, sleeve inserted.

3 rounded sides, bore too small for an 18650 cell.

hcd615 said:

... If so then I will use that U2 for the Milky mod ...

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In your process of determining which one to mod, don't worry about the body. The head is the only part that will be modded (as far as I know anyway). You will be able to swap the bodies or tailcaps whenever you want.

I would get 2 sets of fresh SF cells, and find a dark room and compare the beams. If one has a donut hole, poor tint, or lower output, send it along to Milky, regardless of the body it has. If they are all the same, I would very slowly turn the selector ring and see if one of the heads has the issue where it drops to the lowest level briefly before activating the next brightest level. Mine does this, but only happens if you turn v-e-r-y slowly, so it doesn't bother me at all. It might be a good "tie breaker" of sorts if all else is the same though.

So, the two flat sides U2 is the first run? My U2 has two flat sides and will fit an 18650. Is that the 1st gen U2?

socom1970 said:

So, the two flat sides U2 is the first run? My U2 has two flat sides and will fit an 18650. Is that the 1st gen U2?

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I think so. Here'are pics of one of my early U2's, and my most recent one (with a "special" tube); both fit 18650's. Note the both have "flat" sides (which aren't really flat like in the old-style A2):