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. However, the lid may rust if the paint is worn. Replace the lid promptly if rust appears. 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, allowing convenient replacement of lids or rings. Durable, safe, and hygienic. Lids and rings can be replaced separately, offering economical use and meeting various needs. HIGH-QUALITY MATERIALS: Regular mouth mason jar lids are made of tinplate, reusable, resistant to high and low temperatures, and suitable for use in refrigerators, microwave ovens, and dishwashers. Jar rings are compatible with most standard mason jars. MULTIPLE USE: Ideal for sealing mason jars used to store spices, sweets, biscuits, fruits, jams, beverages, tea, coffee, nails, screws, and other small items. NOTE: Please verify the size before purchasing. Material: Tinplate Size: 70 mm / 2.8 inch Color: Silver Package: 24 Pcs x Mason jar lids 24 Pcs x Rings Split