These Wheaton 9mm polypropylene screw caps are designed for use with ABC Vial™ threaded autosampler vials. The cap features the Wheaton "Super Septa", low extractable septa that is optimal for gas chromatography/mass spectrometry (GC/MS). The cap has a 0.005-inch PTFE/0.035-inch red rubber liner. Cap Thread Size: 9mm.