I'm looking for a flexible rubber donut for my custom-made mattebox.
I need one that is about the 4 1/2 inch size at the mattebox end, and about the Series 9 size at the lens end.
I attached some pics for exemplification, and I pointed out what kind of donut I am looking for (credits: two pics from Visual Products and one recently posted by tonaci).
Thanks! If you have one for sale at a reasonable price, please drop me a line.