The copying ring is centred in the base plate of the router with the centring mandrel. This produces uniform routing results. The centring mandrel is suitable for all copying ring sizes|Thanks to the twisted shank, it fits a shank size of both 6.35 mm and 8 mm. Centring of the copying ring at the router. for shank support Ø 6.35 mm and 8 mm for centering the copying rings. for all Festool routers