The product works and is well recognized by my Canon flash (580 EX II and EX RT 600) But two details I will make it back: it's not the same rack system cell that Canon. Although convenient for loading the batteries quickly. There it is necessary to remove the cover completely the product to access the big battery cover. No big deal, but good. The last point is the most annoying flash connector plug that is too long of 2 to 3 mm, the result no seal between the flash and decision and suddenly it takes strength rather than clipped perfectly.