One of the things that Simple brand shoes does to make their shoes more environmentally friendly is make them out of sustainable or recycled materials. Some of the materials they use include recycled inner tubes, recycled bike and car tires, bamboo, organic cotton and silk, natural crepe rubber, latex, felted wool, coconut, hemp, recycled PET and latex elastic, jute, recycled plastics, cork, post-consumer recycled paper, rubbahyde, water based cements, recycled plastics, BLC leather and ISO 14001 suede.