The development of newer and more efficient techniques for sealing mechanical equipment against a variety of liquid, gaseous and granular media, has been rapid and continuous. For many years the standard materials available to users of packed glands were asbestos and various types of common organic fibers, such as ramie, flax, jute and cotton. The last twenty years have been very productive in the development of new materials. A survey of new materials used for Seals is given.