This Coleman branded looped vaporizer was found recently when I bought it assuming it to be a Petromax one. It does not fit the threads of my 1954 Col-Max, threads are finer than Petromax versions. The seating “flange” is also quite distinct from Petromax versions. It appears to be unused. Discussions with fellow collectors points to it being for a Coleman 238A/239. Pity I could not find the lantern it belongs to!