Helly HansenMen's HH Tech Crew Long Sleeve

T-Shirt HH Tech Crew is 100% polyester and found excellent as first layer on its own. I found it excellent considering mechanical resistance and UH protection compared to polypropylene. Apparently polypropylene is not UV resistant so definitely going to use HH Tech Crew as first layer for sunny running days but for runny days I'll stay to HH Lifa polypropylene