Meyer-Optic Görlitz Trioplan N 2,8/100 is portrait lens for 35mm SLR cameras.
This black "N" Trioplan is younger version of classical silver Trioplan 100. Different is color and Aperture. Classical silver Trioplan has 15 blades, this "N" version has only 6 blades. Optical construction is same for both. "N" version is younger but more rare.