Designed to work with most shoe-mounted flashes, this 4500mAh lithium-ion power pack will boost the performance of your speedlights and bare-bulb flashes and provide 900-1800 full-power flashes on a single charge. It also features dual power ports for powering two flashes simultaneously and will even recharge top-end units in just 1 second at full power. Additionally, it recharges in about three hours and features an LED display to alert users to current charge status and overheating warnings. And, it comes with both a belt clip and a shoulder strap for comfortable carrying.