How Do Suction Cups Work.
Gravity and friction are the two main forces that make it possible for suction cups to work. Gravity pulls the molecules in the air toward earth, creating atmospheric pressure of roughly 14.7 pounds per square inch at sea level, which acts in all directions.
When a suction cup is pushed onto a flat, slick, smooth surface, the air underneath is expelled and a vacuum is created. As there is now no air pressure acting under the cup, only atmospheric pressure is being applied to the outside of the cup, so pushing it down onto the surface. Friction keeps the cup from sliding.
Air can eventually leak back under the cup (so equalising the air pressure again), but a higher quality made suction cup like Adams, dramatically slows downs this process and it performs better for longer.
Adams suction cups are made of a proprietary blend of materials that keep them working better and longer than any other cup. Adams cups are shiny on the underside because any matt finish or insufficiently polished mold, automatically means that air is going to leak in through the seal, causing cup failure. The laws of physics being what they are, any suction cup with less than a glossy finish on the underside, around the edge and extending into the cup, simply cannot stick as well.
By further adding a patented quick release tab to remove or re-position (as seen on most of Adams suction cups), this eliminates the damage to the cup edge caused by the "finger nail removal picking action" on cheap suction cups.
Adams suction cups manufactured in the USA also have more superior features. Fix suction cups dry, to clean, flat, smooth, slick/shiny, non-porous, non-textured surfaces like glass, mirrors, glossy plastic, glazed ceramic tiles, car bodywork etc. Always test suction cups are suitable before hanging valuable or fragile items.