Defend against bitter winds and dropping temperatures with the Ergodyne N-Ferno 6815 Full-Face Stretch Cap. Specially engineered as a lightweight tube-style hard hat liner, this winter head sock delivers continuous coverage across your head, ears, and neck. Made from a premium unlined 100% polyester knit fabric, it traps crucial body heat while maintaining maximum breathability to prevent overheating. Its versatile, high-stretch design fits comfortably beneath construction hard hats, welding helmets, or safety caps without altering suspension settings—making it a perfect cold-weather accessory for industrial jobs, freight handling, and outdoor maintenance.