(28/400) Black Fine Ribbed Polypropylene Screw-On Cap with F-217 (Foam) Liner. This cap creates an airtight seal when securely screwed onto the bottle. Polypropylene offers high heat tolerance and fatigue resistance; it’s designed to fit most any container with a 28/400 neck. This cap ensures a secure and reliable seal, enhancing efficiency by making it suitable for industries where freshness and containment are critical. Most suitable for industrial, food, pharmaceuticals, chemicals, and other areas which would benefit from the reliability and durability of this cap.