Army issue grey felted blanket. Public domain.

Felt is a textile material produced by matting, condensing and pressing fibers together. Felt from wool is considered to be the oldest known textile. Stone burial chambers in the Altai Mountains of North Mongolia have been found to contain felt remains dating to around 700 B.C. The excavated tombs showed a broad use of felt, including clothing, jewelry, wall hangings, and elaborate horse blankets. From Siberia and Mongolia, felt making spread across areas held by Turkic-Mongolian tribes. As nomads traveling frequently and living on relatively treeless plains, felt provided housing (yurts, tents), insulation, floor coverings, bedding and clothing.

The compressed fibers of felt result in the textile having unique properties. Felt is simultaneously fire-retardant and self-extinguishing, it damps vibrations and absorbs sounds. Felt can further hold large amounts of fluid without feeling wet, ideal for clothing in cold, damp conditions.

As well as natural fibers of animal fur, wool or hair, felt can be made of synthetic fibers such as petroleum-based acrylic or acrylonitrile or wood pulp-based rayon.