Double or Quad CD Jewel Case Sleeves.
6 x 6-3/4" 2.5 mil POLYETHYLENE. No flap.

Legacy

These have some give, so they will actually fit over any "fat boy" case that also has a cardboard sleeve over it. I ended up taping the bottom corners down that stick out. Great way to preserve cardboard outer sleeves and prevent wear and tear. I would prefer that they had a flap of some kind to seal them, but these will have to do for now.