Durable and insulated with 550-fill down, the warm, cozy Women's Nuptse Mules will be your shoes of choice from fall to spring. Upper: Recycled P.E.T. ripstop upper 550 fill goose down; 100% of our virgin down is certified to the Responsible Down Standard Foldable-heel design allows you to wear it as a mule Webbing pull loops at the heel and instep for easy on/off Sole Unit: Durable rubber outsole for protection whether you're inside or outdoors Outsole made with up to 20% recycled rubber