Big Horn 14102 Clear Router Sub Base Ideal for working on inlays or routing edges and dadoes, this sub base features a generously sized center hole measuring 2-1/2" to accommodate larger bits. Unlike standard black bases, this model is made of sturdy, transparent plastic, so it will not block your view of your workspace. Existing screws from the router base also make for effortless, straightforward installation. Sub base is compatible with Porter-Cable router models 100, 690, 9690, 691, and 693 (5-3/4" Dia)