Locks key number can be changed in place without removing the lock. Cost effective hardware where retrieving keys can be problematic, such as lockers, laundry rooms, etc. Change each locks key number up to 2 times. High security dimple key. Up to 3 million key changes available. (3,000 key changes per master key.) Please specify keyed alike or differently when ordering. Master key available at a surcharge. Includes screws and original keys. 36 mm cylinder models available as special order items.WARNING: This product can expose you to cadmium, chromium, lead, nickel, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65WARNINGs.ca.gov.