I was initially confused as to why this shouldn't be a direct bolt on replacement until I checked the Kwikee website and realized I needed to get the same one. Screw template to make it fit smoothly. The drilling pattern is shown on the Kwikee website. Simply find your current pitch, look at the hole pattern illustrations and choose a replacement from all models that have the same one. I look forward to getting this step and the electric step back. So comfy for me and the dog!