I have the JetBeam RRT-0 with the AA extender, OP reflector and holster. With that extender, it can take AA and 123 sized cells including AA NiMH, AA alkaline, AA lithium, 14500 LiIon, CR123A lithium and RCR123/16340 LiIon. I like the ability to use various cells.
I love the UI too using the control ring to select brightness levels. It is a 4 level light but the low low is available with a twist up a level and then back down and is memorized. Repeat to go back to low. The ring is nice so you can choose the level before turning it on.
As far as brightens levels, it is quite bright on max using 1.2-1.5V cells (AA) but it is very bright using 3.0-3.6V cells (123 sized). The brightness level separation is great even with AA's. The low low is nice for long runtimes or night-adapted use like getting up in the middle of the night to go to the bathroom :candle: . So it is essencially a 5-level light but only 4 are memorized at a time.
The beam is what I would consider "throwy" with a tight bright hotspot but the spill light is still quite adequate. The beam is nice and smooth with the OP reflector and the tint on mine is cool with the XP-E R2 emitter. A warm/neutral version (Q3-5A) is available but you lose a bit of output and an XP-G R5 is newly available for more output and efficiency.
Other features include the ability to tailstand, forward clickie switch and no blinking/flashing modes. I really appreciate that last non-feature in an EDC role. And lastly, it is one nice looking light! JetBeam, IMHO, makes some of the best looking production lights.
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