Well, I would like a window. I have changed my Avatar to a picture of my pump case, it has a hook which goes over the centre of my bra and it hangs below. It’s very comfy as I can’t feel it. I’d love a soft cotton cover in a smaller size. A window would be great as then I wouldn’t have to be continually taking the pump out to make insulin adjustments etc. Also, these ones wear out quite quickly as the soft cotton under the hook, which rubs against the bra, is not reinforced.
Thick material would be no good though as it would make you too hot under your clothes.