Pengwen’s Bioserica Cotton Socks (3 Pack). Crafted with care and eco-consciousness, these socks feature our signature penguin embroidery at the top. Bioserica is a special fiber that blends seamlessly with premium natural materials like silk, merino wool, and bamboo rayon, unlocking endless possibilities for design and comfort. Our socks are both eco-friendly and high-performing, ensuring aesthetics and functionality without compromise. Step into sustainability and style with Pengwen’s Bioserica Cotton Socks.