Designed by ski boot fitters who sought the perfect, no-frills fit, the Bootfit Zero Cushion Snow Sock is built for advanced to expert skiers who demand maximum responsiveness. This sock features a Zero Cushion Profile and is constructed without loose threads inside. It achieves an exceptional, precise fit using the proprietary Foot Moulding Memory Stretch and the Definitive Fit System. Ventilation panels, along with an anti-wrinkling, elasticated instep that prevents bunching underfoot, all combine to enable a better day in your boots. Crafted from the Signature Merino Blend, it offers superior breathability, temperature regulation, and comfort by melding the softness of rayon from bamboo with the natural odor resistance of merino wool. Material Blend 41% Nylon, 33% Rayon from Bamboo, 23% Merino Wool, 3% Elastane Cushioning Zero Cushion Profile Core Fabric Technology Signature Blend of Merino Wool and Rayon from Bamboo Fit System Definitive Fit System, Foot Moulding Memory Stretch Internal Construction Designed with no loose threads on the inside Cuff/Band Support Stay Up Cuff, Elasticated Instep Support, Ankle Band and Achilles Support Seam Type Ghost Seam, Snug Fit Heel Ventilation Mesh Ventilation, Ventilation panels for airflow Certifications 100% Certified Non-Mulesed Merino Wool, Okeo-Tek 100 Certified