Drill Chuck Key Set -- There have 4pcs chuck keys, they are 6mm, 10mm, 13mm, 16mm, different sizes can meet your different drills requirements. Material -- The heavy duty chuck keys are made of high quality solid steel, sturdy and durable, can't be damaged easily. Excellent Workmanship -- The chuck surface is coated with wear resistant rubber, rubberized for a better grip and with the functions of anti-rust, anti-slip design. Easy To Use -- Metal chuck keys easy to use, can changing of your drill bit heads quickly and keep drill bits in place. Application -- Ideal tool kit for unlocking and tightening of various, popular drill chucks to keep drill bits in place. Perfect replacement for lost or damaged chuck keys. 6mm key is for 0.6-6mm drill chuck 10mm key is for 1.5-10mm drill chuck 13mm key is for 1.5-13mm drill chuck 16mm key is for 3-16mm drill chuck Package Contents:4pcs x Chuck Keys