The unibase enables routers with non standard guide bush fittings to accept the range of 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 14inch 8mm 12 mm and 12inch 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 l