SmartWool Women's PHD Run Light Elite Low Cut Pattern Socks 1" high 4" wide 4 Degree Fit System - 4 Compression Bands and flex zones that provide high performance and a secure fit. ReliaWool Technology - Featured in high impact areas, provides the longer lasting protection to keep feet comfortable. 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.