I know the type. The first time I went into our only local vape shop, I asked what external batteries he sold. I find that is a pretty good indicator of the knowledge of the shop owner. He showed me these:
Of course, just the fact it was an MXJO caused my red flag to wave. I asked him if he had ever heard of Battery Mooch. No, he hadn't. I had him pull up Mooch's blog on his laptop and look up that particular battery's bench test results.
MXJO Yellow 30A 2900mAh 18650 Bench Test Results...a preposterously overrated 10A/2700mAh battery
He didn't appear to be fazed in the least. He said he was able to buy these batteries in bulk for a good price, and he couldn't do much better for a 30 amp 2900 mAh battery.
He said he doesn't visit any online vape forums because there are too many "know it alls".
That pretty much sterotyped this vape store manager for me, and I very rarely buy anything from this store.