No size, fits like a small Layer on this warm, lightweight jacket before you hit the hiking trails or head to the studio. Made with Luon® fabric that is soft, sweat-wicking, and four-way stretch. luon® Our sweat-wicking, four-way stretch Luon® fabric is cottony soft—we love this high-performance fabric for its serious stretch and recovery in all our sweaty pursuits sweat-wicking four-way stretch cottony-soft handfeel quick recovery naturally breathable features Designed for: To + from Lycra®: Added Lycra® fibre for stretch and shape retention Thumbholes and cuffins™: Help keep sleeves down and hands warm Slim fit: Fits close to the body Hip length: Layers easily and stays out of your way