Wonderful fisheye lens! Seems to be still produced, with various mounts, but not with the last versions of electrical coupling, like for a Nikon. Unfortunately the one I found uses K mount, I can only use it on a few cameras. No original case, the only provided filter is a neutral one, screwed at the base, body side.
As I have a very few cameras using Pentax K mount, I decided to buy a new one in M42 mount.
Bought new, with original case,notice... The three provided filters are: yellow, yellow-green and red. There is no button for manual position, it can not be used on a Zenit E, except with a little modification.
The Zenitar M comes with a new clip-in cap, adjusted to the shade.