Magnetic Screw Cap found in: Preassembled R.A.M. 9mm Magnetic Screw Thread Cap, Magnetic Screw Cap for Headspace Vials, Magnetic Screw Thread Headspace.. threaded caps will not fit this vial. The part numbers for caps that are available for these vials are SU860101(with PTFE/silicone, 1.3 mm thick), SU860102 (with PTFE/butyl, 1.6 mm thick), and SU860103 (with PTFE/silicone, 1.5 mm thick).