The Unibase enables routers with non-standard guide bush fittings to accept the range of Trend guide bushes. It will fit directly to most routers. Line-up pin used with a 16mm plastic bush to ensure concentricity of the cutter to the guide bush when fitting the sub-base. Suits collet sizes 1/4 inch, 8mm, 12mm and 1/2 inch. 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.