The North Face Thermoball Traction Mule II Boots - Women's Warm ThermoBall powered by PrimaLoft insulated mule Lightweight ThermoBall insulation retains warmth in cold, wet conditions Durable, water-resistant, element-shedding, 100% recycled P.E.T. ripstop upper 40% recycled rubber outsole for supreme traction Stretch-gore panel integrated into the tongue for no-fuss, easy on/off