Seals are used to prevent material transfer between two rooms. They can be both static (without movement) and dynamic (with realtive motion). Sealing materials are often elastomers (FKM, NBR, EPDM ...) or plastics, but also graphite or soft metals are in use. In many cases, lubricants are necessary. Partly simply to keep the seals soft, but above all to minimize friction forces and/or material wear.