What is a Micropipette?
• Micropipette is a tool that we use to transfer various small volumes of liquid. 
• Micropipette are used to measure in specific microliter (μl) volume.
Fig 1.1 National Cancer institute Biotech laboratory

• Micropipettes are named for the maximum volume they can measure . Micropipettes come in a range of different styles . Different Micropipette have different range which allows you to measure accurately.
Fig 1.2 Different micropipette's  
Some of the Micropipettes are -
Micropipette Max volume Range
 P2 Micropipette 2μl(0.1μl-2μl)
 P20   Micropipette 20μl(2μl-20μl)
 P200  Micropipette 200μl(20μl-200μl)
 P1000 Micropipette 1000μl(100μl-1000μl)

• Depending on the volume you want to measure you use different Micropipettes. 
• The ranges of different Micropipette overlap slightly. For example - if you want to measure 20μl you can either use P20 or P200. 
Ideally the Micropipettes with small range provide us great accuracy.

Micropipette's working parts-
  • The Plunger
  • The Tip Ejector
  • The volume window
  • Tip Ejector Collar
If you will turn the Micropipette you will see a window that displays the volume you want to measure (fig1.3) . This display basically have three numbers on it .
Fig 1.3 The Volume window
Let's take an  example for better understanding - let us assume that you took P20 Micropipette and the window is displaying 0 5 0 .
 So now what does that mean?? 
Look guys every number on a Micropipette is given a position like it can be tens or ones or hundredths . So now back to example P20 
  0 tens
  5 ones
  0 tenths 
This display help us to find that how much micropipette can measure so here P20 measures 5μl.
• But the window is little bit different on different pipettes
 For better understanding let's see one more example P200  and let's take same value i.e 0 5 0 now the values are same but the measuring volume will be different . Let's see how ! 
   0 hundredth
   5 tenths
   0 ones

Same window 0 5 0 but now the measuring volume is 50μl. 
 • Now If you want to change the measuring volumne of that Micropipette ! You want that your P20 should measure 6μl rather than 5μl
This is where the volume changing knob enters! So to change the measuring volumne you just need to Turn the knob and set your desired volume .
In an order to draw up the volume indicated by the window you just need to push the plunger down .
 • The plunger usually have 2 point of resistance or we can say two stops 
• The first volume of resistance or the first stop will push out the exact volume of air Indicated by the window 
This Stop is used when you are drawing up liquid.
•Then the second stop , when ejecting liquid is drawn up.

 • A micropipette is always fitted up with disposable tip on its end. 
Since we all know that working in a sterile condition is one of the most important thing so to stop the cross contamination between the sample. The tip is released after use.
 To attach a tip Micropipette is pressed down onto a tip end that is stored in a tip box.
After using the tip you can remove it by eject button present on Micropipette.

How to hold a Micropipette?
•  The top body of Micropipette should rest on top of your hand and thumb should be on the top
• Now close you fingers hold it comfortably.
• Window will be hidden by your finger position.
• Now rest your thumb on plunger
yes now you are holding the Micropipette  correctly! 
Fig 1.4 How to hold a Micropipette.
Now you all are aware of  what is Micropipette, it's working parts , function of those parts and how to hold a Micropipette.
But Guys this is not it! You need to practice a lot on the holding of Micropipette and disposing tips off and using a plunger, specially the stops.
Since we all know practice makes a man perfect so practice more and more ;) 
Thankyou!