Got one of these to hook up my Scarlett 18i20 to an ART Tube Opto for drum tracking – and just to have those nice, tubey pres whenever I want. I wasn't exactly impressed with the look and feel of it, though; I used to work in a HiFi shop, and our opto cables were thic (only one c).
But hey, I figured it's cheap, and it's just gonna sit at the back of a rack and probably never move again. And guess what? It's worked perfectly. For like... years. Flawlessly. Never even thought about it again.
If you need a cheap way to hook up two ADAT devices in the same rack – you really don't need anything more than this!