These are the Tappi Crown Caps that you would use to create a easily removable, high pressure seal on a champagne bottle. This is used as an intermediary step before you add the champagne cork for long aging of the beverage or for other bottling needs. They are only available in gold caps.
These are designed to work with the following stock items
Emily Wing Capper: 400000001210
29 mm Capping Bell: 400000003917
Champagne Bottles - 29 mm neck : 400000014081
Also, you may need the plastic corks: 400000006727