Big Horn 14102 Transparent Router Base Ideal for working on inlays or routing edges and dadoes. This base has a generously sized hole in the middle of 2.5" for larger bits. Unlike conventional black feet, this model is made of sturdy, transparent plastic so it does not affect the view of your workplace. Existing screws from the router base also allow for effortless and uncomplicated installation. The sub-base is compatible with the Porter cable router models 100, 690, 9690, 691 and 693 (14cm diameter).