C Skins HDI Polypro Men\'s Short Sleeve Thermal Rash Vest 2021 The C Skins HDI Polypro thermal rash vest is designed to keep you warm in the coldest of winter days. It can be worn under a wetsuit as an extra barrier to retain body heat for longer or on it\'s own in warmer climates. The thermal material acts in the same way as thermal underwear but is designed to be worn in the water. FEATURES • Breathable flatlock seams • High lycra collar • Heavy weight Poly Pro lining