This is going to be a long shot, but what the hell. I just picked up a brass barrel lens of some sort. It is 3 1/2" tall and about a 2" diameter. There is only one visible marking on the barrel, a stamped "3". I'm not sure if there are missing pieces, elements, etc. but it doesn't really seem to do anything! When I took the elements out, I can see that they say Darlot Paris on the sides of the elements. At least that is how I decipher it. So based on that crappy description and the attached photos, does anyone have an idea what this lens is and/or what is missing? Thanks in advance.