Wilson special tool for violin is required for mounting the pickups correctly. The 34 mm precision drill and the special handmade 349 mm reamer are required to obtain the maximum output of sound from the 35 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 V pickups. Set contents: Drill and reamer to prepare the holes in the bridge special key for adjusting the volume and a wood stick for correctly dismounting the pickups from the bridge.