All LC/GC Vials, Caps, and Kits Vial inserts available for small volume samples Vials and Caps available in 100 packs E. 18 mm (Magnetic Caps for Headspace) Certified Caps Septa Material A. PTFE/Silicone AR0-815M-13 AR0-81AM-13 AR0-81BM-13 PTFE/Butyl Rubber AR0-814M-13 F. 24 mm (24-414) Bonded-In Caps (-B) Septa Material PTFE/Silicone AR0-8557