The L306 is a white PP plastic 24-400 child-resistant cap with heat induction seal (HIS SG90) liner (for PET and PVC containers only). Child-resistant caps are equipped with a locking mechanism that requires additional effort to open. To be designated as "child-resistant" these caps have undergone the requisite evaluations of a regulatory agency. This closure comes with a heat induction seal (HIS SG90) liner, already placed inside the cap. An SG90 HIS liner is composed of four layers. A heat seal, aluminum foil, and wax are adhered to a foam backing. This seal provides an airtight, tamper-evident hermetic seal when an appropriate heat induction sealing process is applied. This liner should only be paired with containers made of PET or PVC. 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.