I found something interesting I couldn't find any information for.

Fitto Karaoke Boxes

I got two filled with various Hong Kong Karaoke discs (not only from Fitto). I don't know if those came pre-filled or could be bought separately. One came with a catalog / song list for Fitto LAV 8001 to 8030.

Can't be of any help at all with your question, sorry. I just wanted to say I love the design of them. They look like the cover of a Scritti Politti or Duran Duran box set. The architeture style F inner box design looks like the 1980's vomited all over it. Love it!