025 525 1 Sigma Rollerball
Year: 1995.

From 2000/2001 catalog (Portuguese)
"The beautiful black
Black is beautiful - with the rotring lambda series. The black voluminous surface and the diamond-cut handling area offer these writing objects an attractive appearance, firmness, and easy and tireless writing. Available as a fountain pen (M) and rollerball with snap-on cap, ballpoint pen with push button and giant blue fill and mechanical pencil with 0.7 lead. the great beauties!"

This was description for Lambda... Sigma model has only difference in a clip design.
Reminds a lot on 600 series with the grip area accept it's body section is oval shape.
Amazing to hold in hand since the black rubber surface cover.
Only downside is that rubber paint is very delicate and easy to damage...also takes a lot of dust on itself.

Presumably Sigma was first in 1995. and then changed to Lambda in 2001.

Weights 32g.

Sigma is incredibly rare to find today.

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