After a search and some help from this newsgroup I found them at Skyox in
Michigan. They cost around $100.00 and there is a mounting stud that goes on
the side of the headset earcup. The O2 tubing and nasal cannulas then work
like a boom mike. It's a lot less cumbersome than using standard cannulas
around the neck or over the ears, which always uncomfortable under a
headset.