4 Degree Fit System - 4 Compression Bands and flex zones that provide high performance and a secure fit. * High Density Impact Zones with WOW Technology - Higher density SmartWool Duroyarn in the heel and metatarsal areas for added protection and durabvility. * Ultra Light Cushioning - In the sole for comfort and protection against shock and abrasions. * Mesh MVT Zones - Open mesh knitting patterns for maximum ventilation. * Toe Seaming - Flat-Knit Toe Seaming for increased comfort and durability.