The Sanyo 4HR-3UWX 4-AA rechargeable battery pack utilizes the Double X (XX) battery Powered by Eneloop which provides 2500mAh of performance for long lasting, high power capacity, extreme applications. These batteries are bad-ass…. XX batteries are the main reason why my strobes, speedlights, and speedlites work. It provides more than twice the number of flashes per recharge in less than half the time as compared to conventional alkaline batteries! Woot woot!!!
I used to use higher mah batteries but the problem was that the cells couldn’t hold on to the high capacity mah ratings… you literally needed to use them right after a full charge. I travel a lot so I need batteries that will work even after a long standby without having to charge them before use.
…and if you’re asking if the extra 500mah is worth it… when your work depends on it, it’s worth every penny.
I recommend (if you’re a pro) that you stock up on these. I purchased my Sanyo Eneloop XX 2500mAh, High Capacity rechargeable batteries set here... =)