These media bottles are manufactured from 33 expansion, low extractable borosilicate glass conforming to USP Type 1 and ASTM E438 Type 1, Class A Requirements. Includes - 2 (100 mL), 3 (250 mL), 3 (500 mL) & 2 (1,000 mL) Media Bottles; Enhanced graduations andmarking spot made with chemically resistant white enamel paint