Carl Zeiss Jena  Flektogon  20mm f4 ZeBrA

Wide Angle Prime Lens, M42 mount

Serial number 9575356. Made in Germany, DDR.
EXCELLENT working condition. Minimal traces of use.
Focus ring is nice and super smooth.
Aperture blades are snappy at all settings.
There is no oil or rust on aperture blades.

Optic is great. No fungus, no haze, no cleaning marks. 
Filter thread is intact and accepts filters properly.

Lens comes with case, front and rear caps. 

Please check images for more details.