Which type of pipet only measures one volume?

The volumetric pipet is specifically designed for measuring one precise volume of liquid. This type of pipet is often used in analytical chemistry and laboratory settings where accuracy and precision are paramount. It has a single calibration mark and is designed to deliver a specific volume when filled to that mark.

This feature distinguishes the volumetric pipet from other types. For example, graduated pipets have multiple markings and can measure a range of volumes, which allows for versatility but not the absolute precision required for certain analytical applications. Transfer pipets are primarily used for transferring small volumes of liquid without measuring them accurately, and micropipettes also allow for the transfer of varying volumes, often in microliters, but they can measure different volumes as needed. Therefore, the unique design and function of the volumetric pipet make it the correct answer, as it is specifically tailored for delivering one fixed volume consistently.