The Unibase allows routers with non-standard guide bush fittings to accommodate various Trend guide bushes. Will fit directly to most routers.Line-up pin used with a 16 mm plastic bush to ensure concentricity of the cutter to the guide bush when fitting the sub-base. Suits collet sizes 1/4inch, 8mm, 12 mm and 1/2inch. Instructions for fitting The line-up pin fit into the collet and is plunged through the router base. The line-up bush is fitted into the Unibase and secured. This is then placed over the line-up pin and rotated in order to line up the fixing holes. The Unibase screws are tightened and then the line-up bush can be replaced with any choice of Trend guide bushes. These range from 10 mm up to 30 mm (GB10 - GB32). For larger diameter cutters a 40 mm guide bush (GB40) is available.