100% 18.5 Micron Merino Wool 230 g/m2 Interlock knit construction * Mock neck for added insulation and 1/4 zip for venting * Flat lock seams to prevent chafing and machine washable and machine dryable * Weight of Garment Size Large = 11.85 oz. (336 grams) * Available in Men"s Sizes: XS to XXXL