Nissin PS 8 flash battery pack

$199 at Amazon, $249 at both Adorama and B&H. The difference is that the $199 item is shipped from England, FREE though. It just takes a week to get here rather than several days. But the savings is enormous, enough to buy a second swap-out battery cartridge and double the shots per charge, for about the same price as some other packs on the market.

This pack has a recharge time of less than a second. https://www.youtube.co​m/watch?v=4Orxa2axwcM

I ordered one and will post a review.