The Kaweco Classic Sport Fountain Pen.

The Sport closely follows it's timeless, original 1935 octagonal design. The oversized cap arrangement creates a small closed pen but a full length open pen when the cap is posted. The cap is threaded to seal, for reliable safety - and there's no need to worry about cap fasteners wearing down after long term use.

Closed, the pen is just 105mm long, open 133mm long. The barrel is 14mm in diameter (around the cap).

Made in Germany, with tough but lightweight ABS/macrolon plastic. 
Features the Kaweco logo in metal on the end of the cap.

It uses short/mini standard international ink cartridges, and includes one blue mini ink cartridge.