The L15287WHH125 is a white PP plastic 110-400 ribbed shallow skirt lid with heat induction seal (HIS) liner (for PE and PP containers only). This closure comes with a heat induction seal (HIS) liner, already placed inside the lid. An HIS liner is a metallic disk that provides an airtight, tamper-evident hermetic seal when an appropriate heat induction sealing process is applied. This liner works with PE and PP plastic containers only. For more information on heat induction sealing and available machinery, please read our article, How to use HIS liners and a heat induction sealing machine. This lid is made of white polypropylene (PP) which is highly resistant to heat and fatigue. This is a heavy duty cap. This closure fits a container with a 38-430 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.