Well, with any pocket rocket like this there are going to be severe limitations. Eagletac routinely includes a stepdown after 3 minutes and 20 seconds of burn time. However I did miss that it required 2 RCR's to pump out the lumens. Given that the XM-L2 can push out near 1000 otf lumens on a single 18650 you would think an ever so slightly more efficient LED would be able to do a bit more no problem...