Spritz/Speed Reading Apps

I used to have an app called Litz that used the Spritz technology for speed reading. It seems not to be updated anymore and I‘m looking for an alternative. There a few out there, some pretty expensive.
Does anyone use this kind of reading?

I used it for a while, then forgot about it. I’m not sure it’s really faster than reading a „normal“ text with full concentration. But it forces you to keep this concentration up and guides you through the text until it’s finished.

Instapaper has built-in support for this.


But only for 3 articles if you don’t subscribe.

Sometimes you just need to read a lot of stuff very quickly.