These Kimble Chase KIMAX round-bottomed flasks have a vertical center neck with a 14/20 standard taper outer joint and an angled side neck with a 14/20 standard taper outer joint.
These flasks meet requirements for the American Society for Testing and Materials (ASTM) E438, Type I, Class A, Standard Specification for Glass in Laboratory Apparatus, and the glass conforms to USP Type I requirements. They are made from 33 expansion borosilicate glass, which has a low coefficient of thermal expansion and very high resistance to chemical attack.
Kimble Chase Life Science and Research Products manufactures scientific laboratory glassware under the Kimble Chase KIMAX brand. The company has its origins in Kimble Glass and Kontes Glass and is now a division of The Gerresheimer Group.