We put a lot of thought and engineering into our high-performance Superleggera Shell Jacket and Vest. The main body fabric is Japanese-made Pertex® Quantum, but weve made it without the standard coating so that you get a very small amount of air permeability that lets sweat escape, while the DWR coating will keep light rain at bay. On the back weve used a totally waterproof stretch panel that sheds wheel spray, and the stretch allows for a great close-to-body fit. Best of all, the piece takes up minimal space in a jersey pocket. The vest has mesh panels for extra breathability while the jacket is fully closed for extra protection.