These lids are dishwasher safe and won’t rust with normal use! Leak proof too! Plastic and BPA Free – no chemical leach. Infinitely reusable. The 10mm straw hole will work with most of our straw options. 5 lids, 5 platinum silicone sealing rings, and 5 silicone grommets with plugs per order. If you use Mason jars for drinking every day like we do, you need a supply of high quality straw hole lids. These lids are made to last! They would be perfect for restaurant or bar use – just throw them in the dishwasher along with the Mason jars (and hopefully the reusable straws too). They are made of 18/8 304 grade stainless steel. Stainless Steel is one of the most commonly used materials in the kitchen, used to make cookware, utensils, commercial food processing and storage equipment, and more. Stainless steel will not leach any chemicals into your beverage like plastic can, and it is safe for use with all foods and beverages.