Review on Syntech USB C to Dual HDMI Adapter - Type C Thunderbolt 3 Dual Monitor Adapter for Dell XPS 13/15, Surface Book Pro & More (Windows Compatible Only, Not for Mac) by Jake Powell

The main problem is that many USB->HDMI adapters can only display the SAME full size image of your monitor and duplicate it on multiple external monitors. It's non-trivial to split an image between two monitors so that it EXTENDS the screen (Mail on the left monitor, Chrome on the other). This adapter does just that. Watch your diet. If your USB3 port isn't getting enough power, it may not be enough to power two external monitors and your laptop's internal monitor. In my case, I had to choose a configuration that runs either one internal monitor or two external monitors (Zenbook), otherwise one of the external monitors will go blank. Otherwise the price/quality/support is excellent.