The lids are made of tinplate. The material provides good thermal expansion and contraction properties, ensuring a vacuum-proof and watertight seal when used as a closure. However, the lids may rust if the coating is damaged. Replace the lid immediately if rust appears. EXCELLENT SEALING: The sealing ring inside the mason jar lids ensures reliable performance for food preservation, providing safe storage. SPLIT DESIGN: Each package includes 24 split-type lids, allowing separate replacement of lids or rings. This design is long-lasting, safe, hygienic, and more economical, meeting various needs. HIGH-QUALITY MATERIALS: Regular mouth mason jar lids are made of tinplate, reusable, and resistant to high and low temperatures. 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 confirm 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