Dewalt qz extreme 2 sds plus drill bits 110 1000mm dewalt dt9540 qz this 10 x 160mm drill bit from dewalt has been manufactured to a very high standard courtesy of the superior carbide grade for long life and greater durability while the hardened body offers extra strength and reduced breakage whether you are a profressional tradesman or diy enthusiast the drill bit delivers speed and endurance along with an optimised flute design for efficient debris removal dewalt dt9540 qz extreme