Karter Scientific is a registered trademark in United States of America. To maintain quality control, authorized permission is required in the resale of our products. Karter Scientific cylinders are made of 3.3 Borosilicate glass material for durability, chemical, and temperature resistance. Uniform wall thickness over the entire measurement range, so wedge errors are avoided. Features legible numbers and graduations plus a hexagonal base that prevents rolling. Single Metric Scale, Class B, Spout top with pour out. If you have any questions or concerns, please contact us. We are happy to make it right!