The Wool Crabby Socks are high quality merino wool socks. They are 50% wool, 30% nylon, 15% elastic, and 5% polyester. There are different sock size options. For size guide please see the Crabby Wool Socks image. Features: THE SCIENCE BEHIND COMPRESSION SOCKS - Compression technology enhances both performance and recovery! Compression around the lower leg will decrease blood pooling in your legs and increase blood flow back to your heart, getting you back to homeostasis much quicker. Compression also reduces muscle vibration during high-impact activities such as hiking, snowboarding, skiing, running and mountain biking. This will decrease your recovery time by reducing muscle soreness and fatigue! WHY MERINO WOOL? - Merino Wool is extremely soft and unlike cotton, it is a fabulous insulator, absorbs moisture, still insulates while wet, dries very quickly & has anti-bacterial properties! Merino Wool is ideal for winter months, outdoor activities, activities in which your feet may get wet or activities which cause perspiration. The antibacterial properties also make Crabby Socks odor resistant. It is undoubtedly the superior material for the job! BENEFITS OF OUR ADDED ARCH SUPPORT - Increased arch support will increase your comfort while keeping your feet more stable and the fascia ligaments stretched. This decreases your risk of plantar fasciitis! COMFORT PERFECTED - None of this L/XL nonsense! Our socks come in 7 different sizes from a Men’s 6 (Women's 7.5) to a Men’s 12 (Women’s 13.5) for the perfect fit! Our unique design also features a seamless toe closure, achilles & bottom-foot cushion, woven size label (no tags) and a deep heel pocket. The crew length design acts as the perfect balance of lower leg protection and boot compatibility while allowing more breathability compared to a full-calf compression sock. CRABBY GEAR PRODUCTS ARE DESIGNED FOR THE OUTDOORS - Crabby Gear is passionate about the outdoors! When employees are not at work or with their families, they are often in the mountains hiking, snowboarding, skiing, trail running, backpacking, camping or mountain biking. These amazing socks were designed specifically with these activities in mind! We also want to encourage you to spend more time outdoors, so they’re machine washable too (lay flat to dry).