The OS1st FS6 Performance Foot Sleeve delivers targeted relief for plantar fasciitis, heel pain, arch pain, and swelling with patented Compression Zone Technology that improves circulation, reduces inflammation, and stabilizes the foot. Made from lightweight, breathable, and moisture-wicking fabric, this sleeve offers all-day comfort whether worn under socks, in shoes, or overnight to help ensure a pain-free first step in the morning. Trusted by athletes and medical professionals alike, the FS6 provides medical-grade compression that supports recovery from plantar fasciitis, Achilles tendonitis, and general foot fatigue while keeping you active and comfortable. For the best fit, measure your arch circumference (middle of the foot); sizes range from X-Small (10–15 cm) to XX-Large (33–46 cm), covering US Women’s 4–11+ and Men’s 3–15.5+—if between sizes, choose the larger size.