The Canon FPD-400 is a focus positional servo demand designed for Canon lens controller kits, including the SS-410, SS-41-20, SS-420, SS-42-20, SS-41-IAS and SS-42-IAS. The controller provides precision focus control and is useful in a variety of professional broadcast applications, including live event coverage and sports. Compatible with these Models Canon Lenses J21 J20 H20 J16 J15 H15 J9 H9 J8.