PK90B1/4 is a molded phenolic control knob designed for electronic equipment and instrumentation applications. It features a straight knurl surface with a white indicator dot positioned on the skirt for easy visual reference. The knob incorporates a spun aluminum inlay and is equipped with a single No. 6-32 set screw for secure shaft mounting. With an overall diameter of 1.25 inches (31.8 mm) and a body diameter of 0.985 inches (25.0 mm), this knob provides a comfortable grip and professional appearance. The knob's compact height of 0.098 inches (2.49 mm) and shaft hole diameter of 0.470 inches (11.9 mm) make it suitable for standard control panel installations and audio equipment interfaces.