eBay
This is a Nikon Nikkor 105mm f/2.5 AI lens. #754627. Manual focus, prime focal length, Nikon bayonet mount.  If you're interested in compatibility stuff, Ken Rockwell has some information available online: http://www.kenrockwell.com/nikon/compatibility-lens.htm.  This is even a great lens for a digital user who wants to take advantage of great Nikkor glass at a low price.

The glass is in excellent condition. I would consider it "like new" in this area. There are no chips, scratches, or blemishes in the glass or coating. Only a completely unreasonable person would be able to point out any flaws.

The lens body is in great condition, with only minor wear to the paint on the exterior. You can see in some of the pictures the stratches to the paint forward the focus ring. The flash makes these chips far more visible, and in my opinion, are not very noticeable. 

The lens is in perfect shape mechanically. The focus is precise and perfectly tight, and the aperture ring is moves freely and flawlessly. This lens was a real dream to use.

Needless to say, the aperture blades are completely oil free, and the glass is free of any fungus.

The lens will include a Nikon front lens cap, 3rd party rear lens cap, and case shown.

If you have any questions, feel free to contact me!
Thanks, and happy bidding!