The Mason Bottle Plastic Ring has been designed to replace the standard metal mason jar ring - no more rust.
This product is compatible with any regular-mouth mason jar. It also fits perfectly with Mason Bottle's other products, including our silicone nipples, the sippy straw top and the silicone squeeze pouch.
These rings are great for storing portions of milk or food in the refrigerator or freezer. They can also be used when storing dry goods. But DO NOT use this product for long-term food preservation like canning. For canning, please only use the manufacturer's metal rings and lids.