The Zelen features a breathable knit upper made with rPET recycled material and a silky-smooth sock liner to keep you cool and comfortable mile after mile. The flexible yet durable 5.0 mm FeelTrue sole features a tire-inspired tread to give you confident grip and control on asphalt, cement, and pavement all without sacrificing the ground feel and feedback you love from Xero Shoes. The tension straps, made from earth-friendly recycled materials, are adjustable for added support and stability, allowing you to push further and faster. At a lightweight 6.5 oz per shoe in a womens 7, the barely-there feel of this sustainable runner will have you flying down the road yellin Zelen!