The metal jar cap is suitable for 86mm wide mouth Mason jars.SpecificationColor: Silver ToneMaterial: IronJar Lid Diameter: 86mm/3.4"Jar Ring Size: 89mm x 16mm/3.5" x 0.6" (Dia.*H)Packing List: 1 Set - 10 x Jar Lids and 10 x Jar RingsAdvantage1. This can cap is made of durable iron material with split-type design. There is a sealing coating ring on the inside of the jar lid.2. The edge of the Mason jar lid is designed with non-slip ribbing for easy opening and tightening of the jar cap.3. The jar lid has a good tightness to keep your contents fresh, and it is great for the wide-mouth jar to dry storing or freeze in the refrigerator.InstructionEasy to use - just install the caps on the jar mouth and tighten it to seal.NOTE: Make sure the right size you need before ordering. Manual measurement allows 1mm-2mm of error.