The lids are made of tinplate. The tinplate material has good thermal expansion and contraction. When used as a sealing material, the container is vacuum-proof and watertight. But the lid is prone to rust when the paint is worn. Please replace the lid as soon as it gets rusty. EXCELLENT SEALING: The sealing ring inside the mason jar lids provides good sealing performance for food preservation. Ensures safe storage. SPLIT DESIGN: Each package includes 24 split-type lids, convenient for replacing lids or rings. Long-lasting, safe, and hygienic. The canning lids and rings can be replaced separately, offering economical use and meeting various needs. HIGH-QUALITY MATERIALS: The regular mouth mason jar lids are made of tinplate, reusable multiple times, resistant to high and low temperatures, suitable for use in refrigerators, microwave ovens, and dishwashers. Our jar rings are compatible with most brands of mason jars. MULTIPLE USE: Suitable for sealing mason jars used to store spices, sweets, biscuits, fruits, jams, soft drinks, tea, coffee, nails, screws, and other small items. NOTE: Please verify the size before purchase. Material: Tinplate Size: 70 mm / 2.8 inch Color: Silver Package: 24 Pcs x Mason Jar Lids 24 Pcs x Rings Split