The Prevail Crew Sock is a medium weight performance sock. It is the choice for the sportsman and sportswoman in all of us. The Prevail Crew is a 9" medium weight sock. If you are in the most extreme conditions, you want the Prevail on your feet. This is the choice sock for those that use taller boots for hiking, hunting or even skiing. Reinforced heel and toe and arch support.Alpaca fiber is processed with a biodegradable citrus based cleaner. Altera High Performance Fiber Technology is naturally anti-microbial and flame resistant. Altera enhances the antibacterial properties of the alpaca fiber with an exclusive Silver Infusion Technology, enabling multiple odor-free wears of our alpaca garments without laundering.On a microscopic level, alpaca fleece has a smooth exterior surface, which is why alpaca is as soft as silk. Alpaca features an unique hollow core which allows it to wick moisture away from your skin Alpaca fiber provides up to 30% greater insulation that Merino wool in either hot or cold conditions. Total thermal regulation even when wet!The Prevail Sock is made in the US.45% Alpaca34% Hydrotec15% Lycra1% SilverCare: Machine wash/ no bleach. Tumbler dry low heat or hang dry. Turn inside out for best results.Available in colors: Sage Tweed, Brown Tweed Sold in 3 sizes: Medium 5-9, Large 9-12 and X-Large 12-14