ECO-T has a slightly more pronounced grip section; to help with learning correct writing posture for kids, new enthusiast, and anyone who likes a little bit more structure to the grip area. Cap and end cap also has a rotary triangular shape design.

Pen cap has an inner cap to insure a perfect seal when stored away.
Made for the beginner who just wants to try out fountain pens, all the way to the experts. A good everyday worker.

Piston Filler Fountain pen: Simply unscrew the end cap, dip into ink, screw back the end cap, and your done! Ready to write!! 

• Comes with a medium steel nib
• Colours: Clear/Saffron Yellow
• Pen cap is able to post onto the back of the pen
• Grip diameter: 10mm
• Length (Uncapped): 13.1cm
• *Please note: Ink is NOT included
  

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?)