Introducing the Herberton men's thermal underwear extra knee layer warm leggings fly opening insulated long johns for cold weather, a winter wardrobe essential with a regular fit design, combining casual comfort with functional performance. These thermal long johns provide warmth and flexibility, perfect for layering in cold outdoor activities, work, or sports. Designed to enhance mobility while keeping you warm, crafted with premium fleece and stretch fabric for softness and insulation. The leggings are breathable, lightweight yet durable, resistant to wear, and maintain shape after repeated washing and long-term use. Featuring extra knee padding for protection, elastic cuffs at ankles to prevent slipping during movement, functional fly opening for convenience, tapered fit for streamlined style, and elastic waistband for secure comfort. Soft touch fabric ensures cozy all-day wear. Ideal for winter, fall, outdoor sports, hiking, skiing, camping, work, or lounging. The leggings adapt to layering needs, offering warmth and performance for both casual and athletic activities. Pair with thermal tops or wear alone for effective cold weather protection. Herberton puts care into every garment, from design to production. Each pair of thermal leggings is carefully crafted to provide long-lasting comfort, warmth, and performance, keeping you active and cozy during cold seasons, with functional features that stay in place, do not slip, and enhance everyday winter wear.