Vapor Flask is coming out with a bunch of new gear, they have a small single 26650 version that looks great but all the high 4000+ mAh 26650's are really only 10A. Buddy from VF recommends a 40A 26650... Where do you get one of those? It's just like the wrong labeling on the 18650's, 26650
batteries labeled as 65A for example are really only 10A or 20A in real life.
So instead of a high mAh 26650 you would be better off with a pair of 18650's in parallel. It would have been better if the new VF's took a LiPo pack.
VF stuff starts at 13:20