A volumetric pipette, one mark, Class B is a type of laboratory pipette used for measuring and transferring a precise volume of liquid. The pipette is calibrated to Class B standards, meaning it has a permissible error of ±0.1 mL or ±0.2 mL, depending on the size of the pipette.

This type of pipette has only one mark, indicating the maximum volume that it can hold. To use the pipette, you first fill the pipette to the mark with the liquid you want to measure, then you expel the liquid to bring the volume to exactly at the mark.

The one-mark design makes it easier to use compared to graduated pipettes with multiple volume markings, but it is not as precise. Volumetric pipettes are commonly used in chemistry and biology labs for tasks such as preparing solutions and conducting titrations.