Cold Activated 26mm crown bottle caps. These caps will turn blue and display a "Ready To Drink" message when they reach a cold enough tempearture (41°F)! These caps also have an oxygen absorbing liner that will absorb any oxygen left in the headspace. This helps reduce the oxidation that happens during the bottling process, keeps your home brewed beer tasting fresher, and can extend it's shelf life.
Important to note: These bottle caps activate once you get them wet. Do not wet or sanitize caps in advance of your bottling session or they will not work correctly.