OKW-Tuning-Knob-with-Knurled-Handle-&-Red-Pointer-OKW-A-13-16-240-p-This-OKW-Tuning-Knob-with-Knurled-Handle-&-Red-Pointer-has-been-specifically-designed-for-rotary-potentiometers-with-round-shaft-ends-Featuring-an-axle-diameter-of-4mm-plus-a-lateral-screw-fixing-&-a-red-marking-that-is-clearly-visible-p-OKW-A-13-16-240-Tuning-Knob-Thermoplastic-Body-Red-Marking-Arrow-16-4x 12-3mm