Unlined closures have a 10mil thick membrane molded into the closure eliminating the need for a liner. These unlined closures perform well for single injection testing.

For the lined closures, the 1mm thick polyimide is amber translucent and the white silicone rubber is a high purity rubber composition resulting in low leachables. This new closure has a useable temperature range up to 130°C and performs well up to ten injections.