Iron Man Cr10 extruder knob
thingiverse
Taking the best of both worlds, by combining this amazing Iron Man figure with the practical extruder knob, to see when your filament is being extruded. The arm sticks out just far enough, where it makes it clear to see the rotation, without hitting the z-axis rod. 
Download Model from thingiverse
With this file you will be able to print Iron Man Cr10 extruder knob with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Iron Man Cr10 extruder knob.