As one of the most comfortable base-layer options, check out the TYNDALE MEN’S FRMC LAYER 1 PERFORMANCE LONG SLEEVE FR T-SHIRT. This 4.6 oz. FRMC® Jersey knit garment features flat-lock seam construction with excellent stretch, as well as breathable technology that is moisture wicking and fast drying to regulate body temperature. Arc rated 4.6/ CAT 1 and like all Tyndale products, the layer 1 performance long sleeve is proudly manufactured in the USA.