Wilson special tool is required for mounting the Cello pickups correctly. The 49 mm precision drill and the special handmade 499 mm reamer are required to obtain the maximum output of sound from the 501 mm piezo pickups. A wood stick is required to remove the pickups from the tight fit in the bridge. Please note: Special tools are included when buying type C pickups. Set contents: Drill and reamer to prepare the holes and a wood stick for removing the pickups from the bridge correctly.