Material composition and purpose: A breathable blend of 48% neoprene foam, 30% polyurethane foam, and 17% polyester fiber, designed to keep you warm in extreme cold while maintaining breathability. Seamless locking design for comfort and protection: Soft fleece lining combined with a seamless locking design allows smooth, secure integration with your helmet, delivering snug fit and reliable protection without bulk or gaps. Allseason warmth and performance: Enhances helmet comfort across the year as a fourseason upgrade, providing breathable warmth that adapts to changing weather while supporting consistent comfort during rides. Extended ear protection and wind resistance: Windproof coverage with enhanced warmth retention around the ears to prevent ear freezing, offering maximum coverage for cycling, skiing, and snowboarding. Compatibility and fit: Designed to integrate smoothly with helmets, ensuring a secure, comfortable fit that stays in place during movement. Practical use scenarios: Winter cycling in cold, windy conditions to stay warm without overheating. Skiing or snowboarding under a helmet, maintaining ear warmth and wind protection. Outdoor commuting or activities in chilly weather where lightweight helmet insulation is beneficial.