WindWall fabric is a proprietary wind-resistant fleece from The North Face. WindWall utilizes a unique fabric-bonding process that allows a limited degree of external air permeability (approximately 20 CFM), thereby drastically reducing the effects of wind chill and enhancing the user's warmth and comfort. WindWall 1 fabric has a mesh liner and WindWall 2 fabric has a grid fleece liner for even greater insulation.