Evening BCUK,
I've recently taken up SCUBA diving and am looking for dive torches. In doing so, I've come across plenty of ~1000 lumen torches, running on a single 3500 mAh 18650, and most estimate runtimes of 1hr30-2hrs.
However, this Xtar D20, also using a single 3500 mAh 18650 claims 4hr...