The Nissin PS 8 Power Pack is a dedicated high voltage battery designed to maximize the performance of a Nikon shoe-mount flash unit. The PS 8 can provide up to 550 full-power flashes on a single charge and will shorten the recharge rate to between 0.5-0.7 seconds. This ensures that during long shoots you will not miss a single moment. The PS 8 can support up to two on-camera flash units at once, meaning that fewer items need to be packed for a shoot. Also, you can regulate the power output to your needs. This keeps you from wasting battery power from damaging your flash. Additionally, the circuitry of the power pack has been redesigned for better heat reduction than older models and has a high-strength plastic housing to cut down on weight. Combine this with the belt clip or included strap and it can be easily carried while shooting. Also included are a power supply cable, battery pack charger, and soft case with rainproof cover.