Canon FD 17mm SSC wide angle. 

This is a rectilinear lens, not a fisheye, so straight horizontal and vertical lines stay straight. The SSC is the "modern" anti-glare coating (by late 70s they stopped putting the SSC on).

This is an FD fit breech lock  - but it has the "A" setting on the aperture ring (the green A) that allows it to be used in priority mode or program mode on the later "New" FD cameras. 

It is a solid, metal, sturdy, lens.  The body shows some wear to paint work - see images - this lens dates from 1977.  THe glass is very good, no scratches, fungus, but usual micro "bubbles" in the glass (with age) when viewed with bright torch shining through.   Focus smooth and nicely damped, blades clean (though hard to see, need a loupe, as the aperture is tiny!), aperture ring fine .

For use on digital (which is most people, I guess), one advantage of this lens (and some other breech FD ones) that you might not know about, is that the aperture will stop down even when not mounted on Canon body (you push the aperture lever up, and it locks in place, so you can use it on digital with adapter without having to get another adapter to allow it to stop down - though better adapters have a stop down lever).

Great on cropped digital sensor, or for video (can stick on camera on tripod and capture groups/rooms easily)  - can also focus down to about 4 inches from end of lens for closeups or weird distorted portraits.  Have put a sample image at end (on Fuji Xpro1).

I'm not using this as I now have a pair that cover either side of 17mm -  the slightly less wide FD 20mm plus a (much more expensive) Nikon 14mm for extra wide shots.

Comes with canon front and rear caps.