The smooth black phenolic PV lined plastic caps are offered in a variety of sizes; match the cap code of the container with the cap code of the plastic caps for proper fit. The PV liner is a polyvinyl film adhered to a white pulp paper backing. It makes for a good liner type for chemical resistance, mild acids, alkalis, solvents, alcohols, oils, and aqueous products; not recommended for active hydrocarbons or bleaches.