Pressed Wool Felt - Produced According to SAE Standrad Pressed wool felt production is an complex process, in our daily life, if you wash the woolen sweater by hot waters, the woolen sweater will be shrink, harden and solid, this is the basic principle of wool felting, so the pressed wool felt is also called wet wool felt. Wool fibers have several barbs, which cannot be seen by our eyes. When the wool fibers are treated by hot water process, the barbs will be open and erect. After a continuous process of pressure, moisture and vibration, the barbs will interlock together and form a felting condition. The grade of pressed wool felt is according to the SAE standard, which determines wool content, density and other physical and mechanical properties of the felt.