Power Supply for Small Barrel

I'm looking for some help for a power supply. The unit says it is DC5V. I thought about looking Fritzing for some possible help regards the amps and other specs. I find only ones that marked as 5.5 mm barrel. The one I'm looking to power is probably 3 to 4 mm barrel.

IMG_20160918_170821_hdr.jpg3112x3112 1.57 MB

Arduino Uno on the bottom and the board on top is what I need the power supply for.

Any help much appreciated.