Many thanks, I was able to put that much together. It just makes little design sense. The stem couldn't just be hollow as rebound damping in the rear shock would require shock oil to be pushed past the adjuster without restriction (that would be compression damping) and return the oil under restriction at the return stroke. Seems that would require reservoir space or two channels in the shock stem. There would be little left of the shock stem, given it's outside diameter, with two bore holes down it's inside, and why? The reservoir is on top, why not control it there. It is a curiosity. If I could remove the screw, all the shock oil would be expelled in a pressurized rush? Unloaded the adjuster doesn't seem to have enough tension to be under pressure.