"The set comes with two inserts and a blank bush guide so you can centre the base exactly on the router. It was quite fiddly to find matching holes on my Erbauer but after turing the base several times I located three holes which secured the base properly. There are a number of different nuts and bolts supplied to fix the base to the router in the kit but some of the holes in the base only accept a small head size which had short threads and I needed small head size and a longer thread so had to find some of my own. It was not a big issue but if you don't have a selection to hand it could be frustrating. The 30mm guide fitted easily with two screws supplied and together it all worked perfectly well."