We are proud to say our slippers are sustainable and we take care of our carbon footprint very seriously! Our upper sections are made from felt which consists of 70% ethically sourced wool, and 30% polyester - which is 100% recycled. Our unique heat regulating Qaiwool lining is 100% natural and is biodegradable. Finally, our outsole is made from GRS-certified recycled TPU which makes them grippy and durable