Gillette Super Adjustable
Plastic Base, Diamond Knurling

These Adjustable's are the last of an era that started in the late 1950's
They had already cut costs by making the base plate in a plastic and I guess that the Diamond knurling was cheaper to produce then their other knurling.
Its a Twist To Open, one piece razor. The handle is aluminium, the base plate plastic. The rest of the parts are Chrome plated brass.
They were produced between 1980-Q1 (A1) and 1988-Q2 (I2) when cartridges started to gain popularity. Remember that Gillette's philosophy was to sell blades, so selling cartridges made so much more sense.

 

SA 109 Diamond SA 109 Diamond SA 109 Diamond
How does it shave?
Its a mild to low medium shaver.
I personally find the handle too long.

SA 109 Diamond SA 109 Diamond SA 109 Diamond