I just ran across this information that I thought I had lost. A year or so ago I was talking on line with Greg Deet I believe his name is. He was one of the guys responsible for getting the UDT Ducks made again. Here are some links to some info he sent me. Dan sells them on his site and I have a pair I've used a few times and they are great. I have a picture of some really cool clear duckfeet prototypes if I can just find it....Anyhow, Enjoy.
http://www.vintagedoublehose.com/downlo ... _Page1.pdf
http://www.vintagedoublehose.com/downlo ... _Page2.pdf