The Louis Garneau Junior’s Mistral Vent Jersey is designed to keep kids cool and protected while enjoying a ride with the family. Made with lightweight Airfit and Airfit Mesh fabric that uses a small inner cell construction to enhance airflow and manage moisture. Rounded collar for comfort. 5″ zipper provides ventilation. Elastic at the hem maintains a perfect fit. Front and back reflective accents for increased visibility during night and early morning rides. UPF/SPF 50 sun protection. 3 back pockets to store your essentials. Semi-relaxed design for moving comfort. Sizing (Chest):á JS: 24 1/2- 26 1/2ö, JM: 27 5/8- 28 3/4ö, JL: 29 7/8ö, JXL: 31″.