This base layer harnesses a smooth, sweat-wicking fabric to keep you cool and dry on warm days. 360° degree stretch ensures long-lasting, unrestrictive comfort in the saddle, while ultra-soft seams with flat lock stitches eliminate bulk when worn under hoodies, jackets and fleeces.To stop you from getting too hot, there are underarm vents for breathability. And UV 50+ protection keeps you safe when the sun comes out.