The Castelli Core Mesh 3 Sleeveless is the perfect base layer for warm-weather cycling. The mesh fabric is incredibly lightweight and breathable, wicking away sweat to keep you cool and dry on the hottest of rides. The sleeveless design allows for maximum airflow, while the high collar provides protection from the sun's harmful rays. With a slim fit and seamless construction, this base layer is designed to fit snugly under your jersey without adding any extra bulk.