ball mason jar regular mouth lids and bands (12-pack) ball for all of your fresh preserving needs, trust the brand whose name is synonymous with canning. these ball 30000 regular mouth lids and bands help create a tight seal on your regular mouth canning jars. when heated during the canning process, the soft, bpa-free sealing material on the underside of the lid seals in freshness and prevents oxygen and bacteria from entering the jar. if properly applied, the initial seal will maintain food quality for over a year. use bands to keep lids securely in place. made of durable tinplate steel, both can be reused for short-term storage purposes. however, the lid's long-term soft sealing functionality is single-use only.