Surefire U2 generations

CELICA XX

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Is it possible to identify the Surefire U2 by looking at pictures only ?

Why do some lights say "DIGITAL U2 ULTRA" and others will just say "U2 Ultra" ?



Which model is newer ?
 

Tiresius

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Color of the threading, number of sides, but most importantly, the serial number.

The newer models utilize a SSC P4 emitter with white threading, complementing 4 sides on the body. Sadly, they do not fit 18650 cells. That's nothing a little boring can't do.

If I remember, the Digital U2 Ultra is the one with lux v emitters. Others can correct me if I'm wrong.
 

Bullzeyebill

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Correct, the earliest U2's used a Lux V LED, and an 18650 fits perfectly. Depending on the vf (forward voltage to the LED) an 18650 worked well with all six light levels. The lower the vf, the better for an 18650. Driver uses a boost circuit to achieve 6+ volts, using two CR123's or one 18650.

Bill
 

Tiresius

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Correct, the earliest U2's used a Lux V LED, and an 18650 fits perfectly. Depending on the vf (forward voltage to the LED) an 18650 worked well with all six light levels. The lower the vf, the better for an 18650. Driver uses a boost circuit to achieve 6+ volts, using two CR123's or one 18650.

Bill

I wanted to cry when my brother lost the U2A I gave him. He never understood the quality in it. To him, it was just another light--a tool. Mines was an older model that uses 4 sides but a bronze color interrior/threading. It utilizes a Lux V emitter that has a relatively warm tint to it and the infamous doughnut ring in the middle. Sadly, it wasn't old enough to utilize the 18650 cells.

To the OP, the Digital U2 Ultra are the older models. The newer ones are called U2 Ultra or in short, U2A. It has four sides and utilizes an SSC P4 emitter that is fairly weak with a single cell. Not to mention, the beam is very bluish but perfect.
 

Kilted

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I still have my old 'Digital U2 Ultra' it takes the 18650 very nicely and I've learned to re-appreciate the warmer tint doughnut hole and all. Truthfully the doughnut hole only shows up during white wall hunting never in actual use. And to many lumen s can be blinding. It has been replace by smaller and lighter SWM V10R/A for EDC.

=D~~ Kilted
 

JBA

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Just looking around this morning and stumbled across this thread. Being a Surefire U2 owner for several years I was curious about a few things. Is there a way to look up the Serial Number and determine what generation U2 this is and what emitter it has? Mine has Digital U2 Ultra written on the outside, it's a round tube and the inside of the battery compartment is bronze in color. Can I run an 18650 in it? Also what (if any) are the advantages of running an 18650 over two CR123's?

Thanks guys!

How has the selector ring held up under long-term use ?

No issues with mine and unfortunately I cannot remember how old it is (at least 4 or 5 years maybe?).
 

Tiresius

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There are three faces on the ones with 18650 body. The body has a plastic inner tube to hold primary cells. If yours has it, it can easily be removed. If not, see if you have a doughnut hole when used on the white wall. I have a feeling that you have the Lux V emitter version.
 

tobrien

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thanks for posting this, I assumed the emitters were the only difference
 

ABTOMAT

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I have an original Lux V U2 and for a while I owned a U2A. Both held up well under very heavy use. I didn't like the U2A though--the beam was blue with a small hotspot, and the selector ring was biased towards the dim end of things. Like dim1-dim2-dim3-dim4-med-high. Apparently Surefire did this with their SSC P4 lights since I had a Titan that was the same way.

My old Lux V doesn't last as long on batteries but it has a nice beam (slight hole), warm tint, and perfect brightness levels.

Just looking around this morning and stumbled across this thread. Being a Surefire U2 owner for several years I was curious about a few things. Is there a way to look up the Serial Number and determine what generation U2 this is and what emitter it has?

Take a look at the emitter. If it's hexagonal and large then it's a Lux V. If it's square and small it's a P4.
 

Eric242

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I was always under the impression Surefire advertised both the Lux V as well as the SSC P4 version with 100 lumens. At least that´s what my catalogs say (2004 = 100 lumens / 2005 = 80 lumens / 2006 = 100L / 2007 = 100L / 2008 = U2 not listed / 2009 = 100L / 2010 = 100L / 2011 = 100L). Now their web pages says 140 lumens. I assume it´s just a corretion of the SSC P4 (U2A) specs while the light is still the same. Or did the U2 get another update?

Eric
 
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WarriorOfLight

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I have 4 SF U2, two SSC P4 and two Lux V, both SSC P4 are much brighter than the Lux V and are comparable with lights in the 150-200 Lumens range.
 

bluebonnet

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I was always under the impression Surefire advertised both the Lux V as well as the SSC P4 version with 100 lumens. At least that´s what my catalogs say (2004 = 100 lumens / 2005 = 80 lumens / 2006 = 100L / 2007 = 100L / 2008 = U2 not listed / 2009 = 100L / 2010 = 100L / 2011 = 100L). Now their web pages says 140 lumens. I assume it´s just a corretion of the SSC P4 (U2A) specs while the light is still the same. Or did the U2 get another update?

Eric

Like Eric242, I have the same question. Did the U2 Ultra get another update? Doubt it. There is a product listing for the U2 in the Surefire 2013 catalog, but no photo. Guess I better go ahead and purchase a unit just in case Surefire discontinues the U2 in the near future.
 
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cland72

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I believe the P4 version has always pushed 140 lumens, and has just recently had the specs updated to reflect that. I highly doubt they've updated the light.
 

KITROBASKIN

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The early (A prefix on serial#) U2 I've had all these years sat around when rechargeable battery flashlights came to light. Since finding out an 18650 works fine in it, been using it some but it just doesn't fit in really well. If only they could replace the head with a setup that could get 800 or so lumens of nice tint. Not going to happen I'm afraid. It is hard to part with it, and it's probably only worth about $100, right?
 

cland72

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Personally I wish they'd found a way to make the U2 have a Z44 bezel with the anti roll part being the selector ring. THAT would've been badass.
 

tobrien

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I believe the P4 version has always pushed 140 lumens, and has just recently had the specs updated to reflect that. I highly doubt they've updated the light.
good thought
Personally I wish they'd found a way to make the U2 have a Z44 bezel with the anti roll part being the selector ring. THAT would've been badass.

another good thought! haha that would've been legit!
 

bluebonnet

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I believe the P4 version has always pushed 140 lumens, and has just recently had the specs updated to reflect that. I highly doubt they've updated the light.

I agree. Surefire is not advertising their 140 max spec as an improved version. The updated spec is printed on the Surefire labeled box.
 
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