The pipette is gently pushed/twisted into the tube base of the long arm.
Gently squeeze the upper or middle valve while squeezing the bulb ‐ this will allow the bulb to suck fluid up.
Insert the tip of the pipette into the liquid and then press the middle valve to draw liquid into the pipette to the desired volume.
Move the pipette/bulb assembly into position to expel the liquid.
Some pipettes are calibrated for 'run‐out' by gravity; they retain a drop or two in the pipette ‐ other pipettes are designed for 'blow‐out' to measure the correct volume. A standard three-valve pipette filler bulb, often called a "propipette", is used to safely and accurately draw up and dispense liquids, replacing hazardous mouth pipetting (as below).
The valves are labelled A (Air), S (Suction), and E (Empty) to control liquid flow.
