Package content: a set comes with 10 pieces of mason canning jar replacement metal rings (without lids, the metal rings are sold separately) Material: the ring is made of tinplate, rust proof and durable, can be applied for many times; High and low temperature resistant, so it can be applied in refrigerators, dishwasher and microwave ovens Airtight sealing performance: our sealing rings can make many plastic or metal lids leak proof and air tight, each jar sealing ring features small grooves design for tight and secure fit, not easy to slip or move around, good to protect the food in your jars safe and fresh Size: the inner diameter of the regular mouth metal ring is 5.5 cm/ 2.2 inches, its outer diameter is 7 cm/ 2.8 inches Widely applicable: these canning jar replacement rings are compatible with most mason canning jars, suitable for paired with most bottle, jar to store fruits, cookies, candies, salad, milk, smoothies, tea, coffee, screws or other small objects, come with good sealing, can rest assured to use