Primaloft Sport 40g/m2 Insulated Parts: Covered with a lightweight nylon woven fabric. 4-Way Stretch: For improved freedom of movement. Thumbloops. Formotion: Ultimate performance and comfort while in motion. Insulated Stretch Panel: Offering optimal freedom of movement whilst insulated. Reflective decorative elements. Weight: 12 oz / 350 gram. Athletic fit. 100% nylon.