This is a simple tray insert to store an MD inside of a CD jewel case. The pegs on the outer spine piece will need to be glued into the holes on the inner tray piece, with the flat side of the outer spine facing inwards.

You may find that some MDs are held a bit loosely, this is due to the manufacturing tolerances on the discs themselves. This does allow most discs to come out quite easily, but the distance between the tray and the cover prevents the disc from coming out when the case is closed.

This is loosely based on the design Matti3 uploaded to Thingiverse, though I completely redesigned it from scratch to make the design properly symmetrical, eliminate the need for supports, and improve the fitment in the case.