The Nova System gives you a wide range of profiling options in a single router bit with specially formulated replaceable carbide tips, which are harder, stronger and longer lasting. These Replaceable blades also offer better performance in abrasive material Nova System consists of two body styles, a router bit with a ball bearing guide, designed for use with portable routers and a router bit without a ball bearing guide for surface work or profiling that can be used with portable or CNC machinery. Each body style offers 1/4" and 1/2" shanks. 28 profiles are available for the Nova System. Set consists of Body, two Corner Round replaceable knives, one Chamfer replaceable knives, all necessary tools to change knives and an instructional CD..