So they got named in 2020? I've been building these for years. Edit: Also, they're not as practical as one might think, because they take up a lot of space. I r

So they got named in 2020? I've been building these for years. Edit: Also, they're not as practical as one might think, because they take up a lot of space. I run mine in my basement, but we use single smaller Fellowes and Rabbit Air filters upstairs.