... - material: 100% wool felt, blend wool felt, polyester felt.- technic: needle punched, pressed- thickness: 1mm~40mm- density: 0.1g/cm3~0.7g ... insulation, seal,dustproof,quakeproof,heat-preservated,sound-insulated PROGRESSWOOL→pressed/needle punched→WOOL FELT→dye cut→RING WASHER/FLAT WASHER→packing→YOUR ...