They are specially designed to seal champagne and sparkling wines. They resist to high pressures (up to 6 bar pressure) while maintaining its freshness and effervescence. They can be made up entirely of an agglomerated, micro-agglomerated cork body or by the coupling of both. In the Premium version they consist of an agglomerated cork body and one, two or three natural cork washers glued to the end that will be in contact with the sparkling wine. The washers are made of high quality thin cork (slow growth) and subject to a sterilization process. The bodies are molded with pre-sterilized cork granules with optimized size and density. These caps have excellent mechanical, sealing and sensorial performances, with guaranteed organoleptic neutrality.