Rohs (lead free soldering) can apply, as there is a pcb inside.
I just bought some Xtar 3100mAh 18650... pass on this one ~
True, but RoHS does not apply to batteries. Secondly, yes you can use a lead free soldering process, but most of the PCB components like mosfets, IC's etc, would also need to be lead free.
UL testing costs thousands of dollars, and again I highly doubt the product as a whole (PCB and cell) have passed this process.
It says "safe"?! Anyone going to test it? And since it says "safe", it should give some legal leverage (Consumer Protection Agency, law suits, insurance, fire department) if there's a thermal run away.
Remember though, that the 3100mAh use NNP technology. This is not so good for high drain, and the battery still has almost half it capacity left when its voltage would indicate it was empty when compared to ICR li-ion. Your high power lights may not get the best out of it unless designed to do so, so the new Fenix cell, which should deliver the specification as a minimum, should be a good one.
Of course the price point is important, and I'd be interested to see how long the TK21 will run on Turbo using Fenix's own 18650.
I don't know of any other really high quality well known (manufacturing) brand cell of 2600mah capacity.
Even so, in my opinion that positive contact looks identical to the Sanyo 2600 positive contact, not the Samsung 2600.