The L1234WHH51 is a white PP plastic 89-400 ribbed skirt lid with a heat induction seal (HIS) liner. The HIS liner is a one-piece foam backed heat induction foil innerseal that will provide a clean peel bond to polyethylene and polypropylene containers. Please read 5 seals and how they make perfect liners for your container for more information on liner types. 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 89-400 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.