The Quantum PR-4 Universal AC Module connects in place of PB1 or PB2 battery for the Quantum QPAC flash system. (PAC not needed.) Use it for uninterrupted, all-day operation of your:
Quantum Qflash X2D -- all modes of TTL supported
Quantum X and X2 - straight TTL.
I made the mistake of buying a new battery when I really did not have the activity to use it. Although I faithfully kept it charged monthly, after a year, my X5d will not fire in 400 watt mode. Perhaps the battery is going bad already. Lesson learned. This unit will allow me to save the expense of batteries that do not hold their power and use it in the studio--works great.
Plugs rigtht in to the other modules, light weight, has a decently long cord. Works just fine.