The L807BK is a black PP plastic 24-400 ribbed skirt lid with PP polycone liner. This lid is perfect for chemicals, solvents, oils, essential oils, cleaners, fragrance oils, and more. This cap comes with a polycone liner, a built-in polypropylene (PP) natural-colored conical-shaped liner that provides a tight seal. This lid is made of polypropylene (PP), which means it has a high heat tolerance level and an excellent resistance to fatigue. This closure fits a container with a 24-400 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.