Fabric: 155 g/m2 100%Ã"Â polyester Polartec® Classic 100 Micro * heathers: 182 g/m2 Polartec® Classic Micro—100%Ã"Â polyester (bluesign® approved fabric) * Ultraviolet Protection Factor (UPF) 30 * Provides 10%Ã"Â more warmth and is 50%Ã"Â more thermally efficient than old TKA 100, at 27%Ã"Â less weight * 24%Ã"Â more breathable and 18%Ã"Â more compressible, providing 23 in3 or 0.23 liter of pack space savings