The MFJ-9232 Loop Tuner knobs are criticized for being too small, and not offering enough resolution to properly identify and note the position of the knob.  These replacement knobs offer a number of benefits:

1.) The knob bezel is larger to more precisely position the knob.

2.) The knob has a triangular cut out to precisely see where it is pointing on the silk screened case.

3.) These knobs are a direct fit to the capacitor posts.  The original knobs are actually screw fit onto a plastic post that is screwed onto the capacitor pot posts.

4.) You can reuse the pot screws to affix these replacement knobs.  

Note:  Please note that these fit snug right off of my printer, and are precisely sized to be above the case plate.  Variations in how your MFJ-9232 was assembled/manufactured may cause the dimensions to need tweaking.