From an e-bike forumWhat we do KNOW.
There are NO 3800mAh 18650's on the public market.
The best in the world right now are a claimed 3.4Ah, and only deliver that at 0.25C discharge.
Ultrafire does not, and can not make batteries, it's a guy named Kai and his buddy who shrink-wrap the lots of factory reject cells with various shrink wrap labels that claim various things. They get the reject cells at the cost of the recyclable materials worth.

With protection circuit ?

Not on this end, only a metal cap spot welded flimsily at the edges of the cell to hide it's previous life's scars from spot welded tabs...![]()


Oh, and i fully charged the cell before cutting it open, very disapointed at the lack of smoke.![]()

In the thread linked too above their is a video of him sawing it in half with a hack saw

buy Better batteries and enjoy!