Class-leading aerodynamics paired with all-day comfort. This jersey is engineered to save you watts while managing moisture and providing comfort for the longest rides.

Product features

• CFD-based fabric placement and seam construction
• Castelli engineered Air_O Strecth fabric for breathabiity, comfort and stretch
• Engineered for aero efficiency at 30 to 55 km/h
• To be paired with Bolero SS base layer for added aero gains, or without base layer for hot days
• Airflow shoulder construction
• Elbow-length stretch sleeves with raw-cut edge
• Elastic around waist to keep jersey in place and support pockets
• YKK® Vislon® zipper
• Contains bluesign® certified fabrics

Technical Features

• Breathability: 4/5
• Lightness: 4/5

• Weight: 103gm
• Temperature: 18°C - 35°C / 64°F - 95°F
• Fit: Race

When Castelli engineered the first aero jersey for road racing back in 2006, everyone thought we were crazy, even a few of the pro riders. Back then, aero was only for TTs. Performance clothing meant moisture management. And you could win the Tour de France with a baggy jersey that was little more than a polyester T-shirt with pockets on the back. Even our aerodynamic consultants expected limited, if any, gains, so we named the jersey the Split Second. In the end, the gains were pretty substantial, and we completely revolutionized the look of the pro peloton. We're now on the seventh major revision of that jersey, and we've found even more gains. Still heavily benefitting from CFD analysis of wake flow in the riding position for fabric and seam placement, along with pro rider feedback, this jersey is both fast and comfortable for long days in the saddle. And for those days when it really matters, wear our Bolero SS base layer under the jersey for even larger aero gains.

MINIMUM ORDER QUANTITY (MOQ) OF 10