I went back and checked the instruction sheets - I was close but no cigar --
CUSA sells three variants on this 1/4 inch pencil. Artist, woodworkers, and deluxe wood workers.
The woodworkers pencil is the "tubeless" one - the deluxe woodworkers has a center band and tubes. The lower tube is threaded. The artist has the long tube and bushing with threads.
There are a bunch of mix and match combination with these. but I like the long-dude appearance of the single piece of wood. I just grind off the center band when I want a one piece grip. That works with the PSI 2mm pencil too.
Sorry for creating confusion above --