Great for use indoors, when nails aren't an option or windows are the only option. Our suction cups have a small, triangle, pull tab which is used for breaking the seal, and it is needed. Each cup is capable of supporting three pounds and, if you're tugging on the hook itself to try and detach it, it seems like a lot more. Combine that with our 12 oz. indoor banners or our window banners and, except for really large ones, these will work marvelously.
Ordinary suction cups focus light passing through it like a magnifying glass. Our suciton cups are light-diffusing which lets light pass harmlessly through, keeping your sign safe. Besides that, they operate the same way - pressing them flat, the air squeezes out and then the elasticity of the rubber that the cup is made out of tries to return to its original shape resulting in a vacuum seal by the air pressure difference. Science and signage in perfect harmony, beautiful.