A pair of these socks just wasn't enough for us, they are so comfortable that we made them in a twin pack. The arch bracing helps keep the sock in place during wear whilst the Y shape heel gives an exact fit on the foot. The flat toe seam helps to reduce irritation and rubbing on the toes. Now, a wealth of REPREVE recycled materials in the fabric blend offers customers a greener alternative. 42% polyester, made from 100% recycled materials, mainly from plastic bottles, creates a reprieve for the planet by reducing energy, water and greenhouse gases. REPREVE is one of the most certified and environmentally friendly fibres available worldwide.