Each year, Castelli looks for new features to make their Aero Race Jersey even faster. In 2015, the Aero Race 5.0 Jersey provided a racer with the advantage of a sleek, aerodynamic and completely comfortable race jersey. The new 2016 Castelli Aero Race 5.1 Jersey maintains that race aerodynamics while improving on comfort and durability. Velocity dimpled fabric on the front and compression band around the waist provide a two watt gain in the wind tunnel. The feathery 103 gram weight adds another feature to boost the performance of the rider. The Aero Race 5.1 is 40 grams lighter than a standard jersey and almost as light as Castelliâs Climberâs Jersey. The lightweight polyester fabrics are used not just for their light weight, but also for the fabricâs ability to dry instantly. The 3D mesh creates air space between the fabric and your skin and the polyester capillary action pulls moisture away from the skin. These properties make the 5.1 Jersey great for moist, cool weather. Aerodynamics and comfort are further improved with the compression band around the pockets that keeps the Castelli race jersey from moving or bouncing when you have a heavy load of GUs and water bottles in your three rear jersey pockets. Silicone gripper elastic keeps the jersey from riding up. The full-length YKK Camlock zipper is easy to open when you need some cooling air and the 3D mesh on back and arms circulates air to keep you cool when it gets hot.