Shedding grams and saving watts is tricky business, especially when you're wading through hyperbolic claims and constantly changing technologies to choose kit that will actually make a difference. Before your summer race calendar gets going, upgrade your race kit with Castelli's Aero Race 5. 1 Full Zip Jersey to stay aerodynamic and comfortable as you vie for a spot on the podium. Part of what makes the Aero Race 5. 1 so aerodynamic is its virtually second skin fit, which eliminates any need to size down to ensure the jersey mimics your body movements in the saddle. Castelli crafts the front of the impeccably cut jersey using its Velocity fabric, a featherweight textile engineered with closely woven fibers that usher air over your shoulders and back with their dimpled surface. Castelli, never satisfied with complacency, further improved Velocity this year to enable it to save a claimed two additional watts over last year's version of the fabric, making this the fastest Aero Race to date. On the back, incredibly breathable 3D mesh fabric lifts moisture away from your skin to evaporate before you can think about feeling soggy, while its dimpled surface complements Velocity to help you slice through the wind. Castelli also includes three rear pockets held close to your body by a compressive mesh band for storing race fuel, along with reflective accents to keep the Aero Race as practical as it is aerodynamic.