This is a fantastic tool for downloading and saving video for offline viewing.
However, YouTube's constant changes will sometimes inhabit the extension from working correctly. Today is one of those days. 720p download is not showing up in the download selection for some reason.

YouTube also recently made a big change to their layout on selected users by moving the suggested videos under the video player instead having it on the right side. The video description got moved to the right side of the video player too and this extension did not load in the new layout.
Hopefully, the developer is able to chance upon the new layout and come up with a fix.