This Power Module It can fit for 3 kinds of bread board. It's concave design so
will not waste your proto zone.This breadboard power shield support Mini USB 
power supply and Power jack 7-12V supply. There are two independent power 
that 5V/3.3V optional. Tow power switchs on board can control each side 
voltage independent.
Output voltage: 3.3VDC and 5VDC.
Input voltage: DC 7-12V adapter or 5V Mini USB.
Size: 54mm*31mm*21mm (L*W*H).
Package Included: 1 pcs 3.3v / 5v Breadboard Power Supply Module