Which piece of equipment allows for a more controlled flow of liquid compared to a graduated cylinder?

The volumetric pipette is specifically designed to deliver precise volumes of liquid with a high degree of accuracy and control. Its design allows for the measurement of a single, predetermined volume, making it ideal for applications where exact measurements are critical. The structure of the pipette, which usually features a bulb in the middle and a narrow neck at both ends, enables the user to draw liquid into the pipette by creating a vacuum and then release it with precision. This capability allows for a more controlled flow compared to a graduated cylinder, which is primarily used for measuring and transferring larger volumes of liquid but lacks the fine control that a pipette offers.

In contrast, a first aid kit and an eyewash station do not relate to liquid measurement or flow control. An iron ring is a supporting device used in laboratory setups but does not involve liquid dispensing or measurement. Hence, the volumetric pipette stands out as the right choice for achieving a more controlled flow of liquid.