20 mm Bimetallic Crimp Cap with PTFE Silicone Septa. 20 ml Headspace Vial, Clear Glass, Screw Neck. 18 mm Magnetic Screw Neck with Cap (8mm centre hole) with septa. 40 ml Clear Vial with Screw Cap and Septa. 1 ml Shell Vial, 40 X 8.2 mm, clear glass, 1st hydro. class, 8 mm PE-Plug, soft, without insertion barrier for Micro-insert, transparent