Looks like the ones we have for our cats.
They are very, very good suction cups and they tell you how to prepare them properly.
We’ve had both (5kg) cats on one having a play fight and there were no issues.
I'm sure they work well - at least while we have "some regulatory capacity" (thank you scotus).
Windows make me nervous. a broken pane probably could be an easy replacement - but mine are not new and I worry about "project creep".
("honey- why DON"T we get know windows, now...😬)
Had one of those window seat and 4+ cats. Big cats. within a week heard a commotion. Window shelf on floor and cats untangling themselves. It is not made to hold more than one cat. Definitely not for groups of 2+, 13-pound cats.