A range of 4 mL vials , 12 mL vials, 22 mL vials, or 40 mL vials are available. You can choice from either clear glass storage vials or amber glass storage vials. Open top storage screw caps are lined with PTFE/silicone for excellent sealability and chemical resistance. Closed storage screw caps, also known as closed storage caps are PTFE-lined