24/400 mm CT (continuous thread) Black Ribbed PolyCone Lined Phenolic Cap. These caps are designed to form an exceptionally tight seal. The PolyCone liner is made of an oil-resistant plastic, offering a superior chemical barrier. Scroll down to the From the Blog section to learn more about our Amber Bottles, Lids & Droppers. This cap fits any of the containers under the Product Accessories below. Jars are sold separately by case quantity. Lids are sold by the piece or case.