This \\\"half of R1\\\" pullover is deceptively light for its warmth. You can slip it on when your exertion level is high but you can't risk going without thermal protection. Using R1's smooth jersey face but a lighter-weight yarn, R.5 has an internal grid construction for warmth, breathability and speedy moisture transfer. It dries in a flash. Both men's and women's have raglan sleeves and a low stand-up collar for comfortable layering. Contoured seams shape the women's top.