One of my favorite Add-Ons. It works to download almost all videos from almost all sites. Only a select few sites don't work. It can happen that a download stops with a broken file, but just redownloading usually fixes that for me, so it's not a big deal. Has helped me a lot in downloading videos that i would have otherwise had to search for for a long time.And it's free with no hidden costs or premium bullshit like many other Add-Ons do. There is no reason not to have this.