Fits over the standard ProGrip™ rail system. The unit is fitted with two ball bearings for smooth sliding along ProGrip™ rails. This is an ideal attachment for precision routing operations as the router can be moved in and out from the rail with a knurled steel knob and brass locking ring. Designed to be used in routers with the USA style guide bush system. Micro Dado includes the basic unit together with the brass USA style guide bush. Router machine and ProGrip™ rail not included.