The North Face Youth ThermoBall(TM) Traction Mule II The North Face Youth ThermoBall(TM) Traction Mule II gives kids the warm, easy comfort they need for everything from indoor lounging to quick trips outside. ThermoBall(TM) recycled insulation keeps feet cozy even when damp, while the soft fleece lining adds next-level warmth. A collapsible heel and elastic side panels make slipping them on effortless, and the full rubber outsole provides solid traction indoors or outdoors. Cozy, durable, and ready for anything, these are the mules kids reach for every day. Details Insulation: ThermoBall(TM) 100% recycled polyester insulation for lightweight warmth Lining: Soft fleece lining for added comfort Outsole: Durable rubber outsole for dependable indoor/outdoor traction Fit: Collapsible heel with elastic side panels for quick, easy on/off