Who does not 2 DisplayPort outputs has (which is given only at the Retina MacBooks), which must be either modest with an external monitor, or choose the Matrox DualHead solution. Or - and this was now my version for cost reasons - a USB video adapter.
Rather by accident I came across the I-TEC USB adapter, which were priced at an acceptable level for a test purchase. The positive reviews of the older USB2.0 variants have been buying just made me even though I could see no support for Mac from the documents.
However, since 20.3. a new driver for the device available:
By means of this simple-to-install driver was the first time the display adapter connected 2nd screen immediately. The monitor was displayed properly on OSX, could be configured and placed and provides the desktop of enlargement is perfectly self-2 window With Youtube Videos are displayed perfectly without grumbling or delays -. The data transfer via USB 3.0 is therefore perfectly adequate!
Therefore my full recommendation for this little white box for those who want to extend their desktop using two external screens!