borrowing from our premium headwear development, the FSTTShirt adopts a fully recycled COOLmatic | PLUS MIKRAmesh fabric for lightweight, quick dry with a cooling and anti odor finish. reflective details keep you lit from dusk to dawn. engineered side vents, keeps things nice and breezy. flatlock stitching and critical welding alleviate much maligned chafing and elevate this essential run T to premium status