Screw-on lids are closures that twist onto the top of containers, providing a secure seal. They are commonly used for jars, bottles, and other storage items, ensuring that contents remain fresh and protected from contamination. The design typically features a threaded edge that matches the container's opening, allowing for easy application and removal. These lids are made from various materials, including plastic and metal, and come in different sizes to fit a wide range of containers. Their convenience and effectiveness make them popular in both household and industrial settings, such as in the packaging of food and beverages.