METAL OUTER BOWL
This strange pipe is marked Kirsten and pat & pats pend - M
Hard to think of this as originating in Seattle, but on checking it is believed to be a very early Kirsten certainly pre O rings. Some research needed on this one still as no one seems to have actually seen a Kirsten with a metal bowl, not even a briar liner
I am not convinced yet that is not a home made alteration for a pot pipe
I am indebted to John Harper for images and details.