Gray PTFE/Pharma-fix Butyl Septa, Φ20*3mm. C201. 20mm Crimp-top Aluminum Cap, 9.5mm Centre Hole. BC202. 20mm Crimp-top Blue Magnetic Aluminum Cap, 8mm Centre Hole. SC201201. White PTFE/White Silicone Septa, 20mm Crimp-top Aluminum Cap, 9.5mm Centre Hole. SCS201201.