Pointer Knob with Set Screw 

Pointer knobs with index. These can be found on a ton of production pedals and are great for customizing any of your pedals or when building a pedal.  

Diameter at a the base is 3/4" and about 1/2" tall. These knobs are found on almost all effects pedals and guitars and secure tightly.

The set screw knobs will fit 1/4" shafts.