Thanks, this looks like a real low IR performer. Interestingly I just tested a purple Efest 4200mAh I got from MTN this March, and the curve looks different. The one I tested has the hump around mid-discharge, similar to the vappower 4200mAh 26650 cell you tested. I guess this is an example of how Efest rewraps cells and you won’t necessarily get the same cell when you buy. Fortunately, from what I’ve seen, they use quality cells.