The batteries are of course Li-Ion batteries and have a nominal 7.2V 1650mAh, which is slightly less than the original Canon batteries that are advertised with 1800mAh. In practice, it makes it but in my experience not noticeable. I can not tell the difference with the Canon original. Likewise, allowing the battery without any problems in the Canon charger to charge and the remaining time display will appear correctly in the camera. So all round no problems in my 5D Mark III.
Much more there is to say, because everything works as it should. In this respect, there is a buy recommendation from me, even though I am an advocate of original accessories otherwise. But half the price and 100% function is already a word.