The main body of the Lombardia shoe cover is constructed from Capo's Vento DWR fabric. Vento features DWR (durable wind resistant) membrane, with an elastic lightweight denier construction and micro fleece insulation back. Simply perfect material to use for a shoe cover. Capo uses The Bock System for the zipper. This Proprietary zip stop technology applied to booties to bolster and maintain seam strength and heal cup integrity.