Came early great
Arrived sooner than most international bargain rate shipping. The visual quality of the circuit boards and soldering was first rate. Both modules tested good. Be aware that no manual or documentation is included.That is to be expected for such a low price.I did a web search for "B3603 DC-DC Digital Control Step-down Module User Manual" and found a useful PDF. The one I found was a poor translation to English but was not too difficult to follow.