The rubber gaskets on Grolsch-type bottles tend to age with use - especially if cleaned with harsh chemicals or at high temperatures. These replacement gaskets are perfect to revitalize your aging flip-tops and ensure a quality, dependable seal. Made from food-grade silicon which is soft and BPA free. Boil resistant and dishwasher safe. They are molded so the size is uniform unlike the rubber ones which can vary is thickness. Color may vary. Choose below to purchase individually or in 100 count pack.