BBB's BHP 21, as pictured [#6] but for 9/8" threadless ...
It got the steerer length up to where it would have been,
had I been at the assembly bench and said No!
when the steerer tube was about to be cut off too short, for my needs,
on a trekking bike, I bought [3rd hand].

with the added length I was able to add a second [threadless] stem
to mount the bar bag mount on it's own bar tube, lower and closer
to the axis, and still have room for a fork crown headlight mount under the bag...

and there still is a threadless adjustment thru that cap bolt,
because the design of the quill tightening bolt was brilliant.
It is internally threaded, 6mm inside a 6mm hex.