This is the Sanyo Pedal Juice, which is a rechargeable battery pack intended for guitar effects and music related hardware. The basic idea is to provide a clean stable power source for your pedalboard without having to worry about dead batteries or cumbersome power supplies.
The complete system includes a battery pack and a wall adapter (shown here) that is used for recharging. It takes about 3.5 hours to get a full charge on the battery.
The plug on the adapter is a smaller size than the power outputs, which will prevent accidentally connecting it to the wrong jack.
The battery pack is almost exactly the same size as a 125B aluminum box used for many booster pedals (4.7" x 2.56" x 1.65").
There are two standard 2.1mm power jacks that provide the 9v pedal power. One good feature is that the battery pack has a button that allows you to power down all of the pedals connected to it without having to unplug them.
The multi-color LED indicator on the battery pack glows green, orange or red, depending on how much life is left in the battery. The capacity of the power pack is specified as 50 hours at 10 ma., or 17 hours at 100 ma. Each power output can provide 2000 ma, which is more than enough for even the most power hungry pedal. It also has a current limit on the outputs which will break the connection if current in excess of the 2A rating is drawn from the power ports.
Another nice feature is that the power pack will automatically shut down after 10 hours, which prevents totally draining the battery should it be left on after use.
The battery is a 3.7v lithium-ion device, which means there must be a step-up regulator inside to get the 9v for the outputs. The voltage output is filtered so that it is clean and free of noise.
The only negatives that I see for this unit are that there are only 2 power outputs, though you could use a daisy-chain cable to provide more connectors, and you cannot use the unit to power pedals while it is charging.
The unit is solid and well made, and though it only has a 1 year warranty, it should last well beyond that time.