From the manufacturer: Lids are made of FDA and USDA approved, food grade product known as Polyoxymethylene Copolymer (POM) or Acetal Copolymer. They DO NOT contain any Bisphenol A (BPA).

This product is formulated using polyacetal base resin that is compliant for use in food contact applications according to (CFR), Title 21, 177.2470. Any additives that may be present comply with appropriate, specific FDA Regulations.

Limitations:
Types of food: All types of food except foods containing 15 percent or more alcohol.

Conditions of Use: Use temperature not to exceed 250 deg F per 177.2470.

Additionally, this plastic is approved by the USDA for direct contact use with meat and poultry products, as well as meeting the Sanitary Standards 3A Compliance for the Dairy and Food Industries Supply Association (DFISA).

Helpful Hints:

* Jars with nicks or chips in tops will not seal properly.

* Approx. 1 inch of headspace should be allowed for sufficient vacuum.

* Using a towel or something similar while tightening metal band, after processing, will help prevent accidental contact with hot contents.

* Leave metal band on processed goods until contents cool completely.

* Allow processed goods to cool at room temperature for 12-24 hours.

* If you leave metal bands on during storage, store in dry area to prevent rust.

* The rubber rings can be reused if no damage is visible. We suggest they be turned over each use. Previous placement will be evident by seal ring grooves left by lid.