The L540 is a purple PP plastic 20-410 smooth skirt unlined hinged flip top snap dispensing lid with a 0.25 inch orifice. Flip top dispensing lids have a hinge that snaps the lid into place. Because it is made of polypropylene (PP), this hinged lid can be opened and closed thousands of times before breaking. The orifice opening is 0.25". 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 20-410 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.