This Comb Jointing Set can be fitted to all heavy duty routers mounted in a fixed head position. It comprises a set of five 4mm kerf, TCT groovers, mounted on an arbor & three ball bearings. These offer alternative cutting depths & provide a self-guiding facility. D 47.6 mm B 28 mm OL 96 mm Shank Diameter 1/2 inch Timber width max. 40 mm