Its not a sticker. But it does stick. Go on, take a guess, what is it? Good answer: Static Paper. It is a propylene with a static charge. This is what allows Static Paper to adhere trouble-free to every surface which may respectably be referred to as smooth or slightly smooth.
This includes windows and doors of course, but also mirrors, walls, ceilings, car windscreens, fitting rooms and many, many more applications which might spontaneously spring to mind. (provided they are clean and dry) After all, the potential applications for Static Paper are, lets see, well, pretty much infinite