Product review (1 stars): BUYER BEWARE!!
Unless you have a D-shaped stem that is 3/8 in wide, this will NOT fit. The word "Universal" in the description is CRIMINAL. IT IS A LIE!  Additionally, even if the knob fits the controller, the overlay that has the numbers is for a stem that starts low and increased in temperature. Mine is the opposite; it starts high and goes lower. The manufacturers solution? An instruction booklet that has pages of other overlays that you have to send for at an additional $2.00 a pop. Wht couldn't they include a few overlays of different styles and adapters for different stem sizes. THEN it would be universal.
Amazon should stop carrying this product immediately until LUX gets it's act together and puts out a product that lives up to its description.