you will need a 17mm or 20mm Driver with a Coil, this one good for most cree leds (can power only one Led) , the input voltage of the driver is from 3.7v (single cell) to 8.4v (two cells) and the output voltage ranges from 2-3.7V which can power single cell Leds like the XML/XPL etc
I Think you’ll find a better Driver in Lexel’s thread