A suction cup is a device made of flexible material, typically rubber or plastic, that creates a vacuum seal when pressed against a smooth surface. This vacuum allows the suction cup to adhere firmly to surfaces like glass, tiles, or metal without the need for adhesives. Suction cups are commonly used in various applications, including bathroom accessories, car mounts, and toys. The effectiveness of a suction cup depends on factors such as surface texture, cleanliness, and atmospheric pressure. When the air is removed from the space between the suction cup and the surface, it creates a pressure difference that holds the cup in place. This principle is often utilized in products like suction cup hooks and suction cup phone holders.