A very nice silver aluminium knob (plastic core, aluminium shell), approx 17mm wide, 17mm high.
Standard 6mm round shaft size.
You can fit ribbed type shafts or D type. Using a D type shaft you might need to knock back the ribs in the hole slightly (just use a drill bit with your fingers, or even a screw driver's blade) to make the fit a bit easier otherwise it's pretty tight.
Very nice appearance, and the small-size diameter makes it good for fine tuning or if space is at a premium.
Knobs have all sorts of uses, volume knobs, tuning knobs, guitar knobs, stompbox knobs, amp knobs, other musical instrument knobs, scientific equipment knobs, DIY electronic equipment knobs, stereo equipment knobs, knobs knobs knobs!
See my other knobs in larger sizes:
283.mytrademe.info
Rotary encoders too:
283.mytrademe.info