The Right Race Jersey For Speed And ComfortSome 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, 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