100% recycled polyester indoor shoes. Uses recycled PET ripstop material with water-repellent treatment, and the thermoball ecoin salation is used in the filling to prevent loft loss due to wet, and maintain high heat retention. It is environmentally conscious and made to be more responsive to weather changes. Great for winter camping and indoor wear in winter. Material: Upper: Water repellent 100% recycled polyester upper, Primaloft(R) Thermoball(TM) insulation. Bottom unit: Nylon mesh, rubber rug. Features: Indoor shoes/Primaloft Thermoball insulation/EVA insole.