This is a near mint condition Mamiya 645 55mm f2.8 N lens, including both caps.
This lens is in superb condition. Cosmetically it has minimal signs of use, with just typical very minor paint loss on the mounting ring and a faint mark on lens front ring from careless attaching a filter, but the glass is perfect. Mechanically no issues; optically it is as good as you will get.
Now seriously hard to find; this is a superb lens and you will not easily find a better example – or any 55mm lenses at all come to that as everybody wants them. This is the very highly regarded and much improved N version. .