Aileen CSV502 Basic Professional 4/4 Full Size Violin Case Triangular Hard Shell Lightweight, Gray

Is this 100% for a 4/4 sized violin?

Will the case stay open on its own when on a flat surface or does it flop back closed? Also, I cannot tell if it opens 180 degrees or just 90.

Is that suspension? It doesn’t look like so in the pictures.

Can I did a 3/4 volin in this case?