I believe the way they get their cells they are bound by some confidentiality agreements with the manufacturers. If you note on their site they explicitly state do not share info on other websites about their costs which is put in place by the mfg's to prevent other retailers who can't get the same stuff as cheap from being pissed. Wholesalers do this all the time.

All I am saying is that the packs take back more than they are advertised in my experience with the 4000mah packs. Mine are perfectly balanced and operate just fine. Take it for what it is worth. I am sure they can charge at least 50% more than they do for their packs and they still would be the cheapest on the market but they don't.

I bet you the Zippy-R's are "blim" enerland cells but notice that they are only speced as 4800mah, not the 5000mah that a enerland would normally be. Others have reported they actually take more than 4800 too. By slightly changing the rated mah conservatively, it also masks the cell's actual brand.

The bottomline is that they are the best thing going in terms of performance and value. I can't think of any reason to by the name brand stuff again at twice the cost. I certainly don't get twice the performacne out of my flightpower packs.