They aren't for a permanent closure or to keep carbonation. I use these as a method to keep dust and bacteria out of cleaned bottles while in storage. Rather then wasting metal caps these cover up the opening quickly and are completely reusable.
I have 250 BRAND NEW silicone bottle caps that I'm looking to sell. They come in various colors and are great for temporarily sealing a clean beer bottle while in storage. They are made of 100% FDA approved silicone and are completely reusable. There will no longer be the worrying about the...