This is the anti-blister running sock that put WRIGHTSOCK Double Layer on the map! Flat knit design with slightly heavier yarns to meet the rigors of your running regime. These socks can keep you blister-free on every adventure-from a daily 3-mile run to a full marathon. If you want a little more volume and protection in your shoe, Wrightsock&';s Running ll socks should be your choice. Our Blister-Free Running Sock Features Recycled Polyester yarns improve moisture management and increased durability Contoured shape and enhanced anatomically correct fit Stabilizer Zone(TM) in arch locks sock in place Blister-Free socks - No Blisters, Guaranteed! Made in the USA Fiber ContentInner Layer: 70% Recycled Polyester, 26% Nylon, 4% LycraA(R)Outer Layer: 68% Recycled Polyester, 24% Nylon, 8% LycraA(R) Double Layer Seamless Toe Wrightsock&';s Double Layer styles offer a seamless toe like most performance socks do these days; however, as you can see on the below images, Wrightsock&';s seamless toe looks a bit different. This is due to the required attachments that connect the inner and outer layers together for our Double Layer system. Even though it looks a bit odd, our seamless toe acts and feels the same on your foot as any other seamless toe design. Anti-Blister Running Sock Sizing Wrightsock knows that one of the best ways to ensure blister resistance is to find the right fit. You can view a brief overview of our sizing below, or find our full sizing information with care instructions here. We also welcome you to review our FAQ page with any additional questions you may have or contact our professionals for further insights. Thank you for choosing Wrightsock!