What is foil doorknob?

As an AI language model, I don't have any prior experience or knowledge about a specific product called "foil doorknob". However, from a general perspective, a foil doorknob may refer to a doorknob that has been coated or wrapped with a layer of foil for decoration or protection. The foil can come in different colors and finishes (e.g., metallic, matte, glossy) and may be made of various materials, such as aluminum, copper, or gold. Such doorknobs can add a touch of style and elegance to a room or complement the existing décor. However, the durability and longevity of a foil doorknob may depend on the quality of the foil and the environment in which it is installed (e.g., high humidity, corrosive substances).