Kimble Chase KIMAX Class A cylinder is calibrated to deliver, permanently marked with an individual serial number and supplied with a Certificate of Graduation Accuracy. They are supplied with a hexagonal base and a SAFE-GARD bumper. These cylinders are designed from ASTM Specification E1272, Style I, Class A requirements. They meet requirements for the American Society for Testing and Materials (ASTM) E438, Type I, Class A, Standard Specification for Glass in Laboratory Apparatus. Made from 33 expansion borosilicate glass, which has a low coefficient of thermal expansion, very high resistance to chemical attack, and heavy walls that minimize the risk of mechanical breakage when heat is applied. 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.