A volumetric pipet is usually used with which of the following?

The use of a volumetric pipet is commonly associated with a rubber bulb because the bulb provides an efficient and accurate means of drawing liquid into the pipet. A volumetric pipet is designed for precise measurement of a specific volume of liquid, and filling it typically requires the use of a device that can create suction. The rubber bulb is ideal for this purpose; it allows the user to control the amount of liquid being aspirated into the pipet without introducing errors that might arise from using an alternative method, such as manual siphoning.

The other options, while useful in their own right, do not align as closely with the typical operation of a volumetric pipet. Syringes, for instance, are used for precise liquid measurements, but they serve a different function and do not typically accompany volumetric pipets. Magnetic stirrers are used for mixing solutions and are not related to the measurement process of the pipet. Finally, graduated cylinders are designed for measuring and containing liquid but are not intended for the same precise volumetric measurements that a volumetric pipet offers. Thus, the rubber bulb is the most fitting accessory for ensuring accurate liquid measurement with a volumetric pipet.