Preassemble, Pre-slit PTFE/silicone septa + Black screw cap, for 8-425 Screw Vials. SLV20SCH. PTFE/silicone Septa + White/Black Screw Cap With Hole,For 20mL /40mL Vial. SLV20SCS. PTFE/silicone Septa + White/Black Screw Cap Without Hole, For 20mL /40mL Vial. SLV20SAS. Aluminum Septa + White/Black Caps Without Hole, For 20mL /40mL Vial. SLV10/20SCM.