I got 2 sets of these knobs. Originally I had 5 inch flex handle knobs on my Porta II mount.
I had replaced the plastic handle knobs that came with the mount with 2 – 5 inch flex handle knobs.
There are 2 exposed shafts on each axis and I was covering the exposed shafts with these knobs.
But when I saw them up close I decided to replace the flex handle knobs also with these.
My attached picture is of the alt axis with the knobs on. I did the azimuth axis also.
These knobs are very functional and don’t stick out like the flex knobs do.