More than your standard PolyPro, Heatflex is an insulating baselayer, featuring a technical coating called Polygiene. Polygiene is a silver salt solution which inhibits the build up of bacteria making Heatflex odour resistant, warm and super soft on skin. - 180g/sqm polypro - Polygiene Stays Fresh technology - Odour Resistant - Active comfort - Breathable - Excellent moisture wicking - Lightweight - Quick drying - Certified Carbon Neutral Product