How to change or reset your Amazon password Zermatt Wool Felt Shearling Narrow. The BIRKENSTOCK Zermatt is our first true slipper. It features our iconic cork latex footbed, and to keep you extra cozy, its fully lined in genuine shearling that will keep your feet warm all winter long. The upper consists of soft genuine wool. Anatomically shaped cork latex footbed lined with shearling Upper: wool felt Footbed lining: shearling Sole: latex Details: Decorative stitching Made in Portugal Width: Medium Narrow Colour: Athracite