A. The FE575 is the auto-lock version of this lock and the outer lever or knob is always locked, except for the 5 seconds after the PIN code is entered. It is always a storeroom device. The FE595 is the flex-lock version and the outer lever or knob can be unlocked by a turn piece on the inside of the lock. When in the unlocked position the device will act as a passage device, when in the locked position the device will act as storeroom device.