This looks really interesting in dual 21700. Flat enough for a pocket, bright enough for most every thing. Guessing up to 10,000 lumens in XP-L HD, 8000 lumens in SST-20 5000K. Just doubling the Emisar D4S 26650 stats. Maybe a Nitecore EC4 style tail cap with thumb screw. And/or a magnetic charging port similar to Olight, Fenix or Klarus for real life waterproofing.