I was looking for an app similar to Screen Zen which I used on android and this works just as well. Helped me go from 2-4 hours of YouTube every day to about 50 minutes a day, the fact that it shows you your time for the day makes you more aware of the amount of time you waste on useless videos, which helped me start to bring down my time from 50 minutes to about 20 minutes in the past few weeks. This extension really helped me make another big step in my life.

does what it says it does, would be better if it didn't let you see the page it's blocking imo