Polypropylene open-top caps and Teflon/silicone septa. Useful in volatile organic analysis. Of high-quality borosilicate glass. Available in clear or amber. Four classes available: 10 Class: Container, cap and .010” Teflon ® capliner. 1000 Class: Container, cap and Teflon/silicone septa or .030-inch Teflon capliner. 2000 Class: Container