The Dyna-Lite Jackrabbit Pack II contains Nickel Metal Hydride Battery Cells. It can power 140 full power pops when connected to the Dyna-Lite UNI400JRg monolight. It recycles in 6.5 seconds, when used at 320 watt/seconds on a full charge.It is the smallest high voltage power pack available, and includes a multi-voltage, 3 hour charger.