If you own a vintage Neve recording console, Neve outboard gear from the 1970's, or building new gear.  All knob shells and caps are painted to be a close match of the original OEM colors.  Brass inserts are new or reconditioned original brass with new set screws. . Concentric lower knob diameter (includes pointer) is 25mm (.910") and have .253" (6mm)  diameter shaft hole.  Upper knob base diameter is 17mm (.670") with brass insert and .128" (3mm) upper brass shaft hole.  Cap diameter is 15.5mm.  Both knobs include set screw.  Knobs can be ordered with your choice of color cap. Caps are painted in similar color shades of Neve light blue, medium blue, dark blue or black shown in pictures.  You are purchasing one concentric knob with LIGHT BLUE color cap.