KEY CHARTING SYSTEM:
1. Keyed Differ System: Each padlock is keyed differently, supplied with 2 keys per lock. 20000pcs individual padlocks available.
2. Keyed Alike System: Each padlock is keyed the same. 1 key will open all padlocks in each group.
3. Differ & Master Key System: Each padlock is keyed differently, supplied with 2 keys per lock. A master key will override and open any of these padlocks.
4. Alike & Master Key System: Each padlock is keyed the same in one group. A master key will override and open all groups of Alike keyed.
http://www.osha-lock.com/products/2/
