At this time, we do not use the FL-1 standard in rating our lights. A 2 Cell Model will get approximately 8-hours before dropping to ~50 lumens. A 3-Cell goes about 12 hours before dropping to that level.
Using the Low Mode with a High/Low Tailcap, a 2-Cell will last about 40 hours (60 hours for a 3-Cell). Using the Strobe on a High/Strobe Tailcap will extend battery life about 50% compared to "High".