missing the 16,but was there ever one?
8" ritco
one marked heavy duty
some are black??
(http://i287.photobucket.com/albums/ll153/richpoor1/th_001-146.jpg) (http://s287.photobucket.com/user/richpoor1/media/001-146.jpg.html)
The black ones are suppose to be the early wrenches.
As far as I know they go from 6" - 60",
6,8,10,12,14,18,24,36,48,60.
I have never seen a straight Ridgid 16" pipe wrench, of any age. I have however seen a 16" offset pipe wrench.
They could be out there, but ive never saw them.