Phenolic polycone caps (100x)Phenolic polycone lined polypropylene caps for GL18 bottles. These caps offer an exceptionally tight seal, making them superior to regular unlined plastic caps which are widely sold elsewhere which are prone to leaking, permeability and degradation when used for perfumery. The regular (polypropylene) polycone caps can be upgraded to phenolic polycone caps, adding a second layer of protection. Phenolic plastic is exceptionally chemically resistant and