Measures .678" diameter at the bottom edge, .430" overall height. Tiny slotted brass set screw fixing to 1/4" solid shaft pots. Fine stylish but affordable choice for 'boutique' effects pedals. Styling similar to the old DAKA-WARE knobs we sell on the Angela Instruments website. Many old stomp boxes (MXR etc.) and vintage guitar amps (El-Cheap Harmony etc.) were rigged with similar knobs.