Vial Storage Rack for 6, 10, or 20 mL Headspace Vials, 36 Vial Capacity, Polypropylene, ea. 18 mm Magnetic Screw-Thread Headspace Caps and Blue PTFE/Silicone, 1.5 mm thick Septa for SPME, 100-pk. 18 mm Magnetic Screw-Thread Headspace Caps and Red PTFE/Silicone, 1.9 mm thick Septa, 100-pk.