The AllPoints Foodservice Parts & Supplies 221657 Control Knob is designed for precise temperature control in various foodservice equipment. With a diameter of 2-1/2 inches and a 3/16-inch D-stem flat design, this knob features clearly marked settings from Off to Hi, including preheat and multiple temperature levels (2-3-4-5-6-7). It is compatible with a range of Star Wells warmer models, including Mod-100D, Mod-200, Mod-200D, Mod-200Dm, Mod-400D, Mod-500, Mod-500D, Mod-500Dm, as well as SS series models such as SS-10, SS-10D, SS-206, SS-206D, SS-206E, SS-206Ed, SS-206Er, SS-206Erd, SS-4, SS-4D, SS-8, and SS-8D. This durable and reliable control knob ensures efficient operation and easy adjustments for optimal food warming.