Durable and insulated with 550 fill goose down. the Men's Nuptse Mule will be your shoe of choice from fall to spring. UPPER/ 100% recycled P.E.T. ripstop upper / 550 fill goose down / At The North Face. all of our down is either certified to the Responsible Down Standard or recycled / 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. made with up to 20% recycled rubber. offers protection whether you're inside or outdoors