This heavyweight base layer uses synthetic Phase SV material, providing excellent durability and warmth. Midweight Phase AR material is used on the back, underarms, and sleeves for improved breathability, making it suitable for long hikes and high-output outdoor activities. Features: - Trim fit design with room to layer a tight-fitting t-shirt underneath - Ideal for winter and spring/autumn hiking, balancing freedom of movement and comfort - Midweight material on the back, underarms, and sleeves for enhanced breathability Issues: - Logo on the left shoulder is peeling - Pilling (fabric pills) visible on the sleeves