Thermo Scientific™ 13mm Autosampler Vial Septa. 13mm Septa for use with threaded caps Snap/Crimp Caps are available in PTFE/ Red Rubber, PTFE/Silicone or Red PTFE/White Silicone/Red PTFE. Pricing and Availability. Thermo Scientific™ Tuf-Bond™ PTFE/Silicone Discs. Discs that combine the inertness of PTFE with the resealability of silicone.