We partnered with Polartec® to deliver this exceptionally comfortable, flame-resistant baselayer that holds up on the job. With moisture-wicking technology and breathable fabric, it's a go-to as a layering piece or on its own in warmer weather. FR Polartec Baselayer Product Features : Polartec® Power Dry® for rapid moisture wickingGreater Arm Mobility™ helps extend arm and shoulder range-of-motion so you can move freelyMoisture Movement Technology™ helps wick moisture away from the skin to keep you dry and comfortable, Crew neckTaped inside back seam reduces irritationContrast coverstitch Men's Flame-Resistant Polartec Baselayer in Light Grey, Size: Small by Ariat