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