going to copy this over straight from the compatibility chart...
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for 2xRCR123 the following can be used.
Leefbody 1x18650 w/C tail and head, +SF compatible tail-cap/bezel. +++
Surefire G2, 6P, C2, Z2, G2Z, M2. +++
Wolf-Eyes 6 series sniper (non-turbo). +++
DX "JALL" ++
Ultrafire/Superfire 2 cell: WF501B, WF502B, ++(some rare UF heads don't fit LF lamps)
Cabellas XPG 6V 2 cell +++
G&P 6P, T-6 +++
Brinkman Maxfire LX +++ (requires removal of built in reflector, lamps don't seat perfectly centered)
Pila GL2 ++
Huntlight FT-01 +
Pelican M6 new version only +
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for 3xCR123 or 2x17500
Leefbody 2x18500 w/C tail and head, +SF compatible tail-cap/bezel. +++
Surefire [G2, 6P, C2, Z2, G2Z, M2] +1 cell extender ++(some extenders fit 17mm cells, some don't)
Surefire G3, 9P, C3, +++
Wolf-Eyes 9 series Raider (non-turbo) +++
Ultrafire/Superfire 3 cell: WF501C, WF502C, ++(some rare UF heads don't fit LF lamps)
Cabellas XPG 9V 3 cell +++
G&P 9P, T-9 +++
Pila GL3 ++
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for 3xCR123 or 2x18500
Leefbody 2x18500 w/C tail and head, +SF compatible tail-cap/bezel. +++
Wolf-Eyes 9 series Raider (non-turbo) +++
Pila GL3 ++
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as for cheap 2xRCR123 options.... the DX "jall" might be a good host. But if you don't intend on ever needing 18mm cell support, then I would just suggest a brinkman maxfire for $17 at target. but If you are willing to up the ante a bit, a WE 6 series or a SF G2 would be the preferred options, but the G2 doesn't come stock with a clicker, it's a push-n-twist. There's also some new G&P products being sold under the name "spiderfire" if I recall, they are basically G&P T series with a different look to em, the advantage of the G&P stuff is lower price than SF but the threads are SF compatible, so they have lots of lego options.
Some ultrafire heads are too "thick" in the metal to accommodate the fatter base of the LF lamps... here is a picture of the difference...
if you look close, you'll see that the non-compatible version has a different taper to the head, and deeper "fins," while the compatible version has shallower fins, the taper stretches down the body more gradually... the design difference is slight, but the deep finned version has to have thicker metal there to accommodate those fins.
you might be able to distinguish by looking at the pictures online... The good news is that I think the version that fits the LF lamps is the most recent production of the ultrafires, so most of the stuff being sold now should fit.
