Those are usually just calcium chloride in a bag, it's very hygroscopic and fairly cheap... also makes a halfway decent de-icer. The issue I see with this thin-

Those are usually just calcium chloride in a bag, it's very hygroscopic and fairly cheap... also makes a halfway decent de-icer. The issue I see with this thin-film method is that no mention is made of the rate of production at a given relative humidity for a given area of the film. It's interesting, but without the details (and with a lot of PR speak) I'm skeptical as hell about this in practice.