DQG Tiny 18650 is the smallest but it is not very good quality. My next smallest is the Sunwayman C20C then Nitecore EC21 and Roche F6, these are all very good.
Sunwayman C20C goes for $59.95 at Illumn or Banggood, I payed under $40 for mine when on special. Just found it for $53 at Fasttech.
Roche F6 goes for $22.50 at Banggood. Great light for the money.
I like the size of the eagle eyes x6, the head is a bit thicker but it’s still easyly pocketable and has good brightness and throw which always lacks on the tube style lights.
Look at this comparison pic:
From left to right: Olight S20 Baton, Convoy S2JM, Eagle Eye X6 SE, Imalent DD2R, Crelant V6CS
I have the XM-L2 S15 Baton a nice light, but it has the worst tint of any LED light I own. Real shame. I’ve read it’s the AR glass that does it, but I’ve never been able to remove the bezel thus far to confirm.