This is a mint condition Mamiya 645 55mm f2.8 C lens, including both caps.
This lens has just been fully serviced. It is in is perfect mechanical condition. No problems at all, aperture really fast without any sticking. There are only absolutely minimal signs of use, just really minimal paint loss on mount. Optically it is as good as you will get, perfect glass with no issues at all.
Now seriously hard to find; this is a really superb lens and you will not find a better example.