Master Key is purchased separately in "Accessories" tab Gym Locker Locks The Perfect Locker Lock The SX-575 combination lock for lockers is the best choice for everyday use. It is an all metal, four-dial combination lock that very sturdy and secure. The dials are large making it easy to read and operate. With over 10,000 possible combinations know that your possessions will be safe. Dual access of this lock, through combination or key, makes it the perfect choice to manage and access your locker. One manager key works on all locks in the group. One Key included. No Hassle Due To Lost or Forgotten Combinations Never again throw away a locker lock due to a lost combination. The master key function allows not only overriding the combination, but also allows lost combination discovery and reset. These functions make this school lock ideal for institutions where the master key is available for administrative purposes. Setting the Locks for Locker Factory Default is 0-0-0-0 Open the shackle and rotate it 90 degrees until the notch on the shackle lines up with notch in the shackle opening Press down and keep the shackle pressed down while setting the combination dials to your desired code Let go of the shackle and your combination padlock is ready to use! Scramble the dials on the locker lock to lock Master Key Instructions Insert master key Turn the key 90 degrees to open the lock and release the shackle Turn the dials until they stop The dials are now showing the combination your lock is set to. After you have discovered the code, close the shackle and remove the key. Your Gym Locker Lock is now ready for use and can be reset. Please see instructions for setting your combination. SX-575 Dimensions Shackle Diameter = 1/4 inch Shackle Clearance = 1 inch Lock Height (including shackle) = 3 3/16 inch Body Width = 1 5/8 inch Body Height = 2 inches