The LILIPUT ballpoint from Kaweco, made of stainless steel, is particularly sustainable.  It is made entirely in Germany and thus goes through very short transport routes.  The stainless steel is blued by hand. Therefore, each pen is unique.
 
Choose either Capped Ballpoint OR Uncapped (click) Ballpoint version.
 
The body, made of high-quality stainless steel, gives this ball pen exceptional haptics and elegance.

The pen includes a blue 1mm refill that slides easily on paper.