The two classes are Course A and Class B. Class A pipettes are made to specific tolerances, or "mistake boundaries". Course B are allowed two times the error limits of Course A. The category specification or serial quantity of Course B aren't marked. Pipettes are used to provide compact volumes https://typesofpipettesinchemistr91111.post-blogs.com/50870944/top-latest-five-types-of-pipette-ppt-urban-news