Ibis Scientific 11mm Clear Snap Cap, PTFE/Silicone, Pre-Slit Polyethylene (Cap), Silicone/PTFE (Septa) Septum: Blue PTFE/White Silicone, Pre-slit: Vial Closure Size: 11mm: Thickness (Metric) 1.0mm: Quantity: 100: Type: Snap Cap with Septum: Item Description: 11mm Snap-It Cap, 6mm hole