I used to have issues in which my window would either swing open or close with the window. Other window holders online only ensure that the window won't swing open.

This one is very niche for my type of window. It fits into a rail in the window and clips into the window sill. The window can be fixed in different positions depending where you click the piece in the window sill.

I uploaded a few STL files with different angles/sizes as I needed them for my own use.