Ventsi, Heter is one of the big battery manufacturers in China. There are others like BAK, Lishen, Power Long Battery, and some lesser players like Yongdeli. Heter may not be the biggest (don't really know), but they have fairly good technology. Enerpower properly rewraps some of its cells, check Test/review of Enerpower 18650 3.2V 1800mAh (Blue), for example. You will clearly see the same top pole geometry, manufacturers usually stick to just one or two top pole geometries, as far as I know.