A gasket is a mechanical device for sealing two mechanical edges. It is a seal in that it prevents something transferring across the 'sealed' boundary. Seals are usually 'o-rings' or flat die cut sheets of a material that can be compressed by the mechanical edges that are sealed being held under pressure. Such materials include polyamide, nylon, and rubber. Gaskets can be tubular rings that fit in groves in the mechanical structure held in place by friction. They can also be held in place by adhesion by a glue or self-adhesion property of the material.Gaskets are used in electronics to help reduce 'electromagnetic interference' (EMI). These types of shields are conductive and complete an electrical circuit between two conductive mechanical parts. The reason for this is to construct a 'Faraday's Cage' to shield internal components and to reduce the amount of spurious EMI signals that are emitted by the device. Gaskets can be used to prevent ingression of water or dust into a product. They can also be designed to survive multiple openings and closures of the device. In some cases, Gaskets are glued or used in such a way that they are destroyed if reopened and have to be replaced. For extreme environments, gaskets and seals must be able to withstand high-temperature ranges and changes, pressure, and even acidity. Read more Read less