Venture further and stay warmer with the PhD Outdoor Heavy Crew. Heavy cushioning and the power of Merino help keep your feet warm, dry and comfortable whether you're out on a multi-day trek or trudging through the snow. Featuring Indestructawool technology for ultimate durability in high wear areas, the 4 Degree elite fit system for a dialed fit and our signature Virtually Seamless toe for extraordinary comfort in any trail shoe.