Due to a credible negative review of this products potential failure modes I am revising this post to not be positive. If you are considering buying it, please
read this review so you have a better idea of what can go wrong with it before you do.
I recently bought this nifty device that sits to the side of a breadboard, accepts a standard DC power plug with any voltage from 7-12 volts or so and supplies two regulated (or non-regulated) sources of power to the power rails on the side.
It cost me under $2, including shipping, which is a low price considering its utility, it seems. However, it has some issues. It has a USB connector but I am going to cover it.
When the jumpers are set - it does supply regulated power, the power rails are changeable and the voltages within spec.
Quality looks adequate- the solder connections look durable.
Of the two AMS1117 labeled voltage regulator chips, one appears to be recycled, but they both work fine so far.
This is the device I have..
http://www.petervis.com/Raspberry_PI/Breadboard_Power_Supply/YwRobot_Breadboard_Power_Supply.html