There is a thread on it somewhere, I think maybe the LEDmuseum.org has a review on his site. From the little I remember it has 3 *banks* of batteries you can put in which essentially can double or triple runtime. I am guessing they are all in parallel perhaps with a diode to isolate them I am rather unsure of that. It looks interesting but if the price is high not worth it due to the fact there is a lot of runtime off AAs for LED lights with just a few LEDs and it is easier to go with C or D cells than double/triple AAs for the same size light.