This form fit long-sleeve base layer uses a wind-proof chest panel & the same stretchable fabric blend from our original 1st layer to provide maximum protection for severe riding & training conditions. New for Fall 2010 Ultimate layering piece for use in cold & windy conditions Chest panel is nylon/spandex with a polyurethane wind-proof laminate Back & arms use a polyester/spandex blend in a &34;semi-mesh&34; construction for a stretchable form fit Minimal neck construction for layering comfort Contoured panels allow for excellent fit without binding Form fit for layering underneath