The 11K5028-JMNB is a control knob accessory manufactured by Grayhill, specifically designed as a Style 5028 knob for use with optical and mechanical encoders and rotary switches. This knob features a 0.250 inch diameter shaft and is constructed from nylon material with a spring clip (press-on) mounting mechanism. The knob has a maximum outer diameter of 1.090 inches (27.69 mm) and a height of 0.710 inches (18.03 mm), with a 0.550 inch (13.97 mm) diameter grip section. It is available in standard black or gray color options and provides a standard fit for Grayhill encoder and rotary switch applications, making it ideal for control interfaces in industrial and electronic equipment where reliable knob operation is required.