Hardly bigger than a Dyna-Lite flash head, the Uni400JR weighs just 3 1/2 lbs. and packs a 400 watt-second wallop. Plugged into an AC outlet you get a 1.4 second recycle time at full power (400 w/s). Full, half, quarter and eighth power settings in 1/3 stop steps provide a four f-stop range. Full tracking quartz modeling light and a built-in slave-eye.Connected to the Jackrabbit high voltage battery pack, the Uni400JR can be used wherever you go. With a freshly charged pack, you can achieve 75 full-power (320 w/s), 150 half-power and 300 quarter-power flashes.