Product review (4 stars): Does what I need it to do
I bought these since they seemed to have the best reviews. I worried they wouldn't stick to the many-times painted heater vent in my kitchen, but they stick fine and haven't fallen off yet (it's been about a month). I wanted to put these over the vents of this heater in my apartment to block cigarette-smoke smells that seem to be coming through it from another apartment. Works like a charm.