This is a high quality agglomerated cork with solid end caps. An agglomerated cork is a cork that is composed of many small pieces that are pressed and adhered together. As the quality of cork has declined many wineries have begun to use alternative corks, such as synthetics or these agglomerated corks to insure a good seal in their wine. These corks offer the assurance of a good seal while at the same time allowing the breathing properties that solid corks offer. Agglomerated corks work best with floor corkers as they are hard to put in with hand corkers (they do not compress as much.)