I have an XTAR SV2 and an older VP1....and of course neither will accommodate the Fenix protected 21700 that came with an HT18. I TRIED to fit it in the SV2 and managed to bork the left bay....now the spring is loose inside the casing. I know I can take it apart and fix it...just haven't had time yet. I started thinking this would be a GREAT excuse to get ONE really NICE charger that could do everything I need to charge - flat top unprotected 18650s, 21700s and also protected versions of the same. Only problem is I can't seem to find one! Fenix makes one that will take the 75mm long 21700s...but only charges at 1 amp. I LOVE the looks of the XTAR Dragon...but it's bay isn't long enough