“I have one of these for a Raspberry pi 3 and another for a Guleek 8s pocket PC. The power supply that came with the Guleek was not up to the job. Rapberry pi 3s need a good powerful power supply. This one is what you need.”
“This official power supply may not be the cheapest supply out there but for a Pi3, I wouldn't use anything else.
Other (cheaper) power supplies have caused me issues with fluctuating power. I have bought several of these and they are as solid as you would expect.”
