The Castelli Aero Race 3.1 Short Sleeve Jersey will be your first step in the direction of feeling like one of the chosen. Though Castelli first burst onto the scene with the Aero Race Jersey back in 2007, it was way ahead of its time, and they have spent each subsequent season improving upon each years' advancements, aided in no small way by their sponsorship of the Cervelo and Garmin teams. This iteration trumps all other versions in aerodynamics. Castelli has tested the jersey, and determined it saves a 12 watts at 40km/h compared to a normal race jersey. Castelli manages these sorts of drag savings by using Velocity with Prosecco fabric, which is a breathable, lightweight material. Its smooth face reduces boundary layer drag while the stretch fit cling-shapes itself to your form without feeling constrictive. The Prosecco treatment is intended to keep you dry by allowing sweat beads to spread out over a larger surface area, allowing for quicker evaporation. At the arm holes, Castelli used their Nervato Fabric; a subtle ribbing at the arms to keep them closer to the skin and more aero by inducing turbulence. Their clever use of the Giro3 integrated grippers you typically see on the shorts for arm hems mean that the arms will practically suction to your body. In addition to the Prosecco hydraulic treatment to keep you dry, Castelli looked to place their open mesh strategically around the back and side panels to increase breathability. The silicone gripper at the waist keeps the jersey's hem tucked close to your shortsThe 35cm YKK camlock zipper allows you to ventilate at will. Castelli worked through more than 70 different prototypes for this jersey, so you can be certain that the Aero Race 3.1 Short Sleeve Jersey will gain a prominent position in your closet. It's available in Black/white and Small through XXX-Large.