• The classic look, with piston filler functionality. 
  
• To fill with ink: unscrew the end cap, immerse the nib and feed into ink, screw back the end cap, clean ink residue from nib and section.
  
• Pen cap will post onto the back of the pen.
  

A quick no brainer guide in choosing nib sizes in an overly complicated fountain pen world:

If you write small, go with an EF
For the normal writer, F is the most popular
If you tend to lean on a bigger font, M will be perfect
B is for statements!! Sign a check in B, write a header in B, do some coloring/shading in B
Stub nibs are italic in writing style (have a special card or invitation to write?)

Check out TWSBI Ink. These Inks made by TWSBI compliment this Pen.