The only Takumar lens with black and chrome "zebra" finish and the last 55/1.8 with 10 aperture blades.
Discontinued in 1959, replaced by lens of the same name but with a different mount with full auto aperture. Optical construction remains the same for both versions and is identical to 55/2.0 except the glass used is of then new higher reflective indexed rare earth glass.

Takumar 55mm f/1.8 versions summary:
Asahi Optical Co. Takumar 55mm f/1.8-22
Asahi Optical Co. Auto-Takumar 55mm f/1.8-22
Asahi Optical Co. Auto-Takumar 55mm f/1.8-16
Asahi Optical Co. Super-Takumar 55mm f/1.8-16
Asahi Optical Co. Super-Multi-Coated Takumar 55mm f/1.8-16
Asahi Optical Co. SMC Takumar 55mm f/1.8-16