Teflon coating on the outer material 4 layer pillow insert Iconic model of the SUBU family. The minimalist heelless design ensures you're ready to go out in seconds, while the ingenious four-layer construction of the sole allows you to experience an unknown level of comfort. The Concept Collection presents a sustainable SUBU in the name of Relax, Recycle, Rethink:The fashion/consumer goods industry, of which we are a part, is considered the second largest environmentally polluting industry. The shift from mass production and consumption to a sustainable industry is not just a personal opinion, but something that needs to be addressed on a global scale. We created a collection made from recycled materials, so you can be part of the solution, as a small member of the industry. RE: Features of the Concept collection:Exterior: 100% recycled PET nylon fabric Interior: Ecological, ECOPET® polyester, Bemberg™ regenerated cellulose fibre. Sole: 20% recycled polystyrene