Made using recycled polyester yarn, this exciting product is amazingly comfortable AND sustainable. It&';s a breathable lightweight+ Double Layer sock and is designed for a low-profile performance fit. Ideal for running and walking. Over 2 plastic bottles used in each pair! OUR RUNNING SOCK FEATURES Over 2 plastic bottles used in each pair of socks Recycled Polyester inner and outer layers Stabilizer Zone(TM) in arch locks sock in place High needle count for added durability Certified, Sustainable, and Blister-Free socks - No Blisters, Guaranteed! BLISTER-FREE RUNNING SOCKS FIBER CONTENT Inner 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 GUIDE Blister prevention requires the right sizing! You can view our sizing chart below. We invite you to contact us for any additional information or head to our FAQ page to find the answers to common customer questions. As a family-owned business, we thank you for choosing Wrightsock anti-blister running socks!