METAL OUTER BOWL
Thomas and Boyd, Luminum-Kraft Products of Cleveland,Ohio came out with these pipes around July 1946. Costing $3.50, there are 2 models, this is the later 50 here and the 35 which has a different sytle of body.
The bowl insert is stated as being of Algerian briar and any standard filter can be fitted inside the stem.
The parts are all interchangeable and briar only bowls were available
The lower image has to be THE state of the art pipe rack for this style of pipes. Storage for spare briar only bowls as an integral part of the rack. Only ever seen one on ebay, I have since acquired a single pipe version with 2 spare briar bowls.
There was also an ejector cigerette holder, the Model 10
26 Aug 1947 US patent # D147,363