Reversible pin technologies Working mechanism Reversible pin tumbler systems contain between 5 and 9 core pins made of hard bronze, and up to 10 horizontal pins (called profile pins). Compared to a wafer sys-tem, this offers more possible combinations, allowing for larger Master & Grand Master Key systems. A series of pins and springs work together to allow the lock to either lock or unlock. In the locked position, the upper pins are forced down, closing the dividing line between the core and body On inserting the correct key, it compresses the springs, pushing all the pins level with the dividing lines. Now you can open the lock. Locked position Open position Conventional pin Wafer locks Return to mechanical technology Return to mechanical technology