There was a time when you'd be looked at sideways for talking about making your kit aerodynamic, but that was a time that Castelli's engineers scoffed at, which is why they were some of the firsts to craft aero kits as far back as 2006. With so much practice, its no surprise to us that the new Aero Limited Edition Full-Zip Jersey is feathery light, while slicing through the wind like none other. This top comes from the original Split Second jersey that Castelli designed all of those years ago, aiming to offer aerodynamic gains that offer free speed. No doubt we've seen some major improvements from that kit of years past, which is apparent with the highly technical fabrics and cut of the new Aero Limited Edition Full Zip. Castelli's designers crafted the Aero Limited Edition Full Zip using CFD analysis of the wake flow that you experience in the riding position, targeting fabrics strategically to smooth out drag, thanks to sleek Velocity Rev2 fabric on the chest and shoulders, and a raw-edge hem that sits snug against your skin for a near seamless transition. On the back you'll find 3D mesh that allows sweat to escape and aids in exceptional moisture management, so you can keep your core temperature down even when the mercury is soaring. In the back there is an extended drop tail hem that allows for perfect pocket placement, while grippers lock the hem to your shorts for a fuss-free fit.