The Whirlpool WP74002115 Range Knob Burner is a replacement knob made for Whirlpool range cooktops. It's the knob that you use to adjust the flame intensity of a particular burner. The knob often has marks that correlate to different flame strengths, ranging from low simmer to high heat. When you turn the knob, it connects to a shaft that controls gas flow to the burner. By adjusting the knob position, you may control the amount of gas that reaches the burner and hence the heat production. A damaged or malfunctioning knob might make temperature control difficult or impossible, perhaps resulting in uneven cooking or safety issues.