This does exactly as it describes. It's fairly easy to open or create new containers. That said, I would like to see a few changes to make it even easier to use.

Right now, when you create a container, that's all you can do on that screen. You can add permanent sites to the containers. You must open the site in the container, then check a box. In one way, this does prevent any errors due to mistyping, but it would be handy if it could search my history or bookmarks and find sites to add as permanently in the container.

It would also be great if there was a "containerize this site" button. Essentially, use the current site as a sample to make a new container and permanent rule.

Additionally, it would be helpful if pre-configured lists (e.g. all social media sites) that could simply be imported for this purpose.