A Double Hop is a unique feature of Windscribe. It allows you to run a proxy over the VPN. In this case, the browser extension is the proxy and the desktop client is the VPN.
This feature allows you to connect to two different or same locations at the same time. For instance, you can use the desktop client to connect to our Toronto - Comfort Zone location while the extension can be used to connect to our New York - Insomnia location.
There are many benefits to using the double hop function such compartmentalization. Lets say that you wanted to have the Amazon Prime app installed and wanted to watch content for the U.S. Then, you open the the desktop client to connect to the U.S. and access the stream. However, at the same time, there is an important file that you want to download which is only available when connected to a U.K. location. Therefore, you can use the browser extension to connect to the U.K. in order to get the file without having to disconnect from the desktop client.