Castelli A Blocco Jersey combines different fabrics and features, each with specific purposes and all designed to keep a cyclist comfortable on many different types of training rides or competitive races. The main fabric is lightweight and quick drying. Mesh side panels enhance breathability and when you need extra cooling, unzip the YKK Vislon zipper and let out body heat. The Castelli A Block jersey has Velocity Rev2 fabric sleeves with no seams at the ends. This feature is fast and exceptionally soft. The jersey is aero, fast, and superbly comfortable. Made of the right combination of fabrics and a careful placement of seams, the jersey fits properly on different body types. While it lies flat against body no matter what position you hold on a bike, it’s not too tight making a great jersey for both competitive weekend rides where you need a good fit and early season 100+ mile endurance rides where you strive for the less restrictive construction needed for long distance comfort. Three rear pockets are sewn into a drop tail. Loaded pockets stay in place and your rear is covered as you are leaned forward in the cycling position. Reflective piping on back improves visibility on low lit training rides and the YKK zipper lies flat and it’s easy to open for extra cooling air.