Headspace vial caps are available in a variety of materials including aluminum, bimetal, and steel; headspace vial cap septa are available in PTFE/silicone, molded PTFE/butyl, and high-temperature varieties. Our headspace vial caps come in either 11 mm, 18 mm, 20 mm or 22 mm sizes. Most used headspace vial caps are crimp cap style. Get Price