https://techcrunch.com/2019/04/10/review-the-199-echo-link-turns-the-fidelity-up-to-11/

The Echo Link takes streaming music and makes it sound better. Just wirelessly connect it to an Echo device and plug it into a set of nice speakers. It’s the missing link.

The Link bridges the gap between streaming music and a nice audio system. Instead of settling for the analog connection of an Echo Dot, the Echo Link serves audio over a digital connection and it makes just enough of a difference to justify the $200 price.