accessory vent shades

[72 K20]

I have a set of accessory vent shades that I purchased to put on my C20, with the windows up they seem pretty secure,, but with the window down they seem like they could easily fall out,, especially if you were driving . The window channels are new. Is there some kind of clips ? Or do you use some kind of adhesive ? Any and all help is appreciated ! I like the looks of these shades and want to have them on my truck as long as they are secure .


Thank You ! Tom

Please note that the pictures are for reference ,, these are not my trucks !