Dynalon®, plastic, premium graduated cylinders are manufactured under strict control. Chemically resistant to most acids, bases and many common solvents. Each cylinder is manually checked and marked with an "H" to confirm premium tolerance has been achieved. These cylinders are manufactured from virgin PMP (polymethylpentene) to provide window-clear transparency and outstanding chemical compatibility. PMP can be sterilized using all common methods including autoclaving. (Repeated autoclaving will affect accuracy.) Shatter resistant - reduce breakage & incidence of injury.