So far so good in the first 5 or so minutes. I needed it to stop me from accidentally watching any video sites while having a VPN with limited gb per month available.

Fantastic! Does exactly what it says and there's lots more under the hood. A pity it's not compatible with Firefox Mobile.

Excellent. Fantastic options. Just what I was looking for (for my autistic son).

This extension is a no-frills, functional block site extension. I personally like using their timed close feature, which closes websites that you blocked automatically so there aren't any distractions. Highly recommend.