The L2393BK is a black PP plastic 38-400 ribbed skirt hinged flip top snap unlined dispensing lid with 0.375 inch orifice. Flip top snap 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 0.325". 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 38-400 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..