Some triathletes choose long sleeves for the extra speed. Some for the comfort. Some for sun protection. This jersey gives you all three.The aerodynamic speed is unmatched. It´s what Castelli does best. We have a year-round testing and development program with the Norwegian Technical University in Trondheim to make our race gear the slickest around.The comfort is what comes from our expert pattern engineers and soft performance Italian fabrics. We reduce the number of seams so that there is less chafing and less to bother you when you should be concentrating on pounding out the run.Sun protection well, you´ve trained untold hours for this day. We focus on speed rather than total sun protection, but we still manage to block 94% of UV rays with our back Velocity mesh fabric that doesn´t compromise speed, comfort or breathability. You may want to add some sunscreen, but this fabric provides UPF 16 protection, which is a significant help. Your cotton T-shirt is probably UPF 8.Take note of the well-thought-out details: Castelli´s generous two pockets lie flat but hold a lot of gear and nutrition. The SnapLock fasteners clip to Castelli shorts to prevent the top from riding up during the swim or bike.Features:- Freedom of movement in the water, aerodynamics on the bike, comfort on the run- Velocity Rev2 aero fabric on front-facing surfaces- UPF 16 Velocity mesh back blocks 94% of UV light with generous breathability- 2 rear pockets lie flat and prevent nutrition from bouncing around- GIRO3 flat gripper elastic lies flat on lower back- SnapLock fastener at lower back to clip to Free Tri Short to prevent riding up during swim or bike leg- YKK® Camlock® zipper- Elbow-length sleeves for maximum aerodynamicsSpecifications:- Weight: 96g