ECO Indigo Blue + Bronze Fountain Pen, TWSBI

The TWSBI ECO fountain pen in Indigo Blue with Bronze trim features a clear acrylic body and gorgeous deep blue cap and turning knob, bronze trim, a piston ink-filling system, smooth-writing steel nib and a screw-on cap. The bronze plating is darker and deeper than the TWSBI rose-gold plating that is currently available. The TWSBI ECO piston ink-filling system uses only bottled ink and the clear body allows the user to view the level of ink remaining in the pen at all times. The pen cap has an inner cap liner that maintains a thorough seal when the pen is not in use.

The traditional mechanism of the fountain pen, combined with a modern industrial design, embodies both the past and the present. This pen runs about the same in length as the Diamond 580 and is just a tiny bit thinner. One difference between the ECO fountain pen and the other TWSBI pens is that the ECO does not have a removable nib unit, and the barrel and nib unit are all one piece. 

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, and do some coloring/shading in B
Stub nibs are italic in writing style (have a special card or invitation to write?)