I bought two of them and compete with my calibrated iCharger (4.2V -> 2.8V, 0.5 A discharge) capacity of 4.7 and 4.8 Ah. Low internal resistance, they are so pretty "resistant to high current," 8A I angetestet. By nonexistent Protection they only have a length of 66mm, it can therefore be wonderful to use in "China Show Flashlights", where often several are 26650 serially connected in series (which causes problems with protected 26650, these are usually 3-5mm longer, which adds up uncomfortable, so that a lamp no longer can screw it properly in extreme cases).
Despite the efficiency of Panasonic NCR18650B they do not reach, in these the ratio of weight to stored energy is still significantly better (3.2 Ah to 48g). So if you want to build a battery pack, which should favor good 18650.
EDIT 2014-11-17: I had acquired two other cells, Table (below) was renewed. The better internal resistance of the two new cells leads almost certainly the fact that I built in the summer of a "super low resistance" contact clamp (clamp around the cells for the measuring process), here not only play throughout large cross sections a role, but also in Specifically, the contact with the cells themselves.
Finally, my table (ID, timestamp, product, internal resistance, capacity, weight, efficiency (Wh / g))
26650-20: 2014-01: Tensai LIC26650 4500 mAh (blue): 55 mOhm: 4707 mAh: 92.3 g: 0.18358 Wh / g
26650-21: 2014-01: Tensai LIC26650 4500 mAh (blue): 53 mOhm: 4802 mAh: 93.3 g: 0.18528 Wh / g
26650-22: 2014-07: Tensai LIC26650 4500 mAh (blue): 41 mOhm: 4741 mAh: 92.2 g: 0.18511 Wh / g
26650-23: 2014-07: Tensai LIC26650 4500 mAh (blue): 40 mOhm: 4766 mAh: 92.7 g: 0.18508 Wh / g
