- Available in Natural red rubber, gray butyl and Teflon® coated butyl
- 7, 13 and 20 mm sizes
Stoppers come in a variety of elastomer formulations. Natural rubber is a general-purpose elastomer used primarily for aqueous liquid fill products in the 4.0-7.5 pH range. Its resealability is an advantage in multi-dose applications. The formulation uses dry natural rubber and no liquid latex. A post-processing cycle (PEP 1) reduces the level of volatile extractables from the rubber component. Butyl stoppers have very low extractable formulations for use with liquid, lyophilized or dry powder products needing protection from oxygen or moisture vapor penetration. Teflon-coated stoppers provide an inert barrier to minimize interaction between reagents and the container.