Parts of a Micropipette – 9 Parts Labeled, Plunger to Tip

All 9 parts on the diagram

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Plunger button Pressed with the thumb to draw liquid up and push it out. It stops twice: the first stop measures the volume, and the second, deeper stop blows out the last drop.
Tip ejector button Pressed to throw off the used tip. So you never have to touch it.
Volume knob Turned to set how much liquid the pipette takes up. One way for more and the other for less.
Volume display A window with three number wheels that shows the set volume. It is a counter, not a screen.
Body (grip) The handle you hold, with the volume display on its front.
Shaft The narrow tube below the body. The tip pushes onto its end, and the piston moves inside it.
Piston A metal or ceramic rod inside the shaft. It slides in an airtight sleeve. As it rises it pulls air out of the tip, and liquid follows.
Tip ejector (arm and collar) The arm and collar down the side of the shaft. Pressing the ejector button slides it down to push the tip off.
Disposable tip The plastic tip that holds the liquid. It is used once and thrown away, so the liquid never touches the pipette itself.

How this list was compiled: Read 2026-09-27. (1) Wikipedia, Air displacement pipette, https://en.wikipedia.org/wiki/Air_displacement_pipette : plunger button, tip ejector button, volume adjustment dial, digital volume indicator, shaft, attachment point for a disposable tip; a metal or ceramic piston in an airtight sleeve; the first and second (blowout) stops; the tip ejector button removes the tip without handling it. Its figure, Gilson schematic.svg (https://commons.wikimedia.org/wiki/File:Gilson_schematic.svg), labels the button, plunger, tip ejector button, tip ejector arm, tip ejector collar, volume adjustment knob, digital volume indicator, body, shaft, piston assembly and tip. (2) Kelli Henry, How to Use a Micropipette, UCLA MCDB (2011), https://www.mcdb.ucla.edu/Research/Goldberg/HC70AL_Su14/pdf/How%20to%20Use%20a%20Micropipettor.pdf (archived 2016-08-20): the round button on the plunger, the window with three digits, the rings turned to set the volume, the grip, the discharge slider that throws off the tip, the two stopping points, the disposable tips. Licence: own work

The drawing: Drawn for this site by script, 2026-09-27. Own work, nothing traced. Licence: own work

How it works

These are the parts of an adjustable micropipette, the air-displacement kind used in school and college labs, standing upright. The shaft is cut open to show the piston.

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Setting and filling

Turn the volume adjustment knob until the display shows the volume you need. Push a disposable tip onto the shaft. Press the plunger button to the first stop, dip the tip in the liquid, and let the button up slowly: the piston rises and draws the liquid in.

Emptying

Press the plunger to the first stop, then on to the second stop to blow out the last drop. Press the tip ejector button, and the tip ejector's arm pushes the used tip off.

Never turn the knob past the pipette's range: that can put it out of calibration.

Questions and answers

What are the two stops on a micropipette?

The first stop is where the plunger meets resistance: it measures the set volume. The second, deeper stop blows out the last drop, and is used only when emptying the tip.

How do you set the volume on a micropipette?

Turn the volume adjustment knob until the display shows the volume, staying within the range marked for that pipette.

Why does a micropipette use disposable tips?

So the liquid never touches the pipette itself. A new tip for each liquid keeps samples from mixing and protects the piston inside.