It's really just a USB to RS485 serial adapter, but the fact that I can use an OTG cable and get info from my charge controller on my phone is great boring. And the price was fantastic! $10 for both parts. You can't beat that! If you're buying a SolarEpic MPPT 40A Solar Charge Controller 150V PV Input Tracer 4215BN, you need to take these cables with you.