The Bosch router kit comes with 3 Bosch keyed bushings, but I needed a larger router bushing and Woodcraft had these nice, shiny, BRASS PC bushings. I can't resist nice brass stuff, and I'm not fond of the Bosch bushings, which lack the "quality" feel and are not as easily found. The base is copied from the Bosch plunge baseplate; the material is scrap Masonite.