The Strobies Pro-Flash Spare Battery serves as additional power for your Pro-Flash. On a full charge, the Pro-Flash Battery provides up to 700 full-power flashes from the Pro-Flash. Using the optional power cables, the Pro-Flash Battery Pack can also be used to power Canon, Nikon, Sony and Metz speedlights, and can offer up to 1400 full-power flashes, while reducing the recycle time. Recharging the exchangeable battery pack takes only three hours. With two ports, the Pro-Flash Battery Pack can power two Pro-Flash or speedlights at one time.