Compatibility with Standard,16 groove, coarse (18 tooth spline) shafts on Bourne pots, AM93, EG112C2, Cherry SE , , , RG series guitar. The top half of the knob is parent, middle and the bottom is silver with black numbers, nice color match with or replacement of parts, these silver knobs added a nice nostalgic look to it and really . Material: Made of high-quality acrylic plastic material with great endurance, to use, smooth and symmetrical, and the numbers are clear. Easy to install: Just need to slightly spread the post with a flat head screwdriver, and they seated level (as level as possible on an archtop) and close to the body. It is a perfect substitute for electric guitar knobs. "caution" very tight on pots, carefully squeeze split shafts, do not force on. Height: 12.1 mm/0.48 in; Top diameter: 23.1 mm/0.91 in; Base diameter: 25.2 mm/1 in; Inner diameter: 6.0 mm/0.24 in. Material: acrylic colour: silver Package Contents: 4 x button caps Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.