Class A pipets are manufactured to provide high accuracy and they are required to meet the requirements and tolerances in ASTM E969 − 02 (Reapproved 2012) “Standard Specification for Glass Volumetric (Transfer) Pipets.” Volumetric pipettes, also known as bulb pipettes, are manual liquid handling devices used in many laboratories for the transfer and dispensing of a single, specific quantity of liquid to a very high degree of accuracy. Generally used for accurate measurement of liquid.