Familiar Birkenstock soles, I wondered how it had been possible to adapt a top felt to make it a comfortable slipper. I trusted the brand, and many took me. The top is made of felt, at the end of the shoe, molded and rigid, so that the shoe holds the foot, protects toes shock, not deformed. The interior is soft (including insole) and thereto is warm especially by the sole which isolates the cold ground and that holds the sole "active". No need socks, even in winter the kitchen tiles!
