Little Mannequin looking Window Stopper which makes the window stay open for venting.
Goes into the slot for the hinges on the Window and braces itself on the windowframe.
For 10 mm slots and 100mm spacing between frame and open Window. (Measured between outer frame plane and in window mounting slot.
Could also easily be lasered or milled. (I added .dxf and pdf for that purpose)
The author marked this model as their own original creation.