The L024BKPL1 is a black metal 58-400 lid with standard plastisol liner. This lid is made of metal, which means it is fairly impervious to most processing methods. However, this metal lid has been fitted with a non-removable vinyl liner called plastisol, which has more restricted temperature and process requirements. When heated, and solidified, this plastisol liner creates an airtight, tamper-evident, hermetic seal. This cap is lined with standard plastisol, which is recommended for a "Hot Fill and Cool" heat process treatment. Minimum sealing temperature (temperature of the product in the jar after capping) is 185°F / 85°C, and the maximum process temperature tolerance is 185°F / 85°C. Please test your product. Container & Packaging Supply is not responsible for compatibility of our products with your product and process. For more information on the different types of plastisol liners and how to use them, please read our article, 3 Types of Plastisol Canning Caps and Why You Need To Know the Difference. This closure fits a container with a 58-400 neck finish. The first number refers to the diameter of the container's opening (in mm). The second number refers to the thread/style/depth of the closure's skirt. Please read 5 seals and how they make perfect liners for your container for more information on liner types.