The OS1st FS4+ Compression Bracing Socks are designed as an all-in-one performance running and recovery sock. They feature OS1st's proprietary design with FS6 technology helping to strengthen your foot and leg structure, providing relief for ankle swelling, varicose veins, plantar fasciitis, achilles tendonitis, heel and arch pain, and shin splints. The FS4+ features a medical-grade, 4 Zones of Compression Technology that is designed for proper foot support and leg support, helping to prevent injuries. They are developed with the highest quality, soft moisture-wicking fabric that contains an anti-odor treatment with additional padding in all the right places.