Review on Converter 5 5 40V Power Supply Module Tools & Equipment for Garage & Shop by David Berry

Really good and reliable little power converter. I had an old tablet that fell over and completely cut the USB power connection. Now I can't turn on or charge this tablet. When I open the tablet, I see that it uses a 4.2 volt battery that powers this very DC/DC converter. I connected the input side to an additional 12 volt power supply and the other end to the battery cables. The tablet now works great with this converter and I can even use it to charge the tablet battery. The converter does not heat up and is very reliable. I would recommend it if you need to convert DC to 4.2 volts.