This blocker may not have all the functionality of others, but, then again, it's less than 100 kB in size, not over 4 MB, and it does literally the same job! Better yet, it works instantly, no need to restart the browser after installation or updating. The only tool I really miss from the bigger extensions is the site sniffer, to see all the allowed and blocked servers a Page accesses.

It works as it says, thank you.

Works great. Used to block procrastination websites