A three-way pipet bulb is used to draw a liquid into any type of pipet.
A three-way bulb is often chosen because it reduces the possibility of contact with the liquid, and any liquid drawn into a pipet can easily be held in the pipet until delivery. The three valves provide a convenience not found in the standard bulb, however, many people require practice using the bulb before using the bulb to deliver a liquid during an experiment.
You should familiarize yourself with the function of each valve and practice using the three-way bulb before starting an experiment that is dependent on your pipetting technique.
