Abstract: A master key board device for the retention, protection, and control of keys. The device is preferably wall mountable, having a face plate containing slots for a desired number of keys. Each key slot has an associated locking device which is controlled by a universal key. The locking device carries an arm which engages specially modified keys to retain them in the key board, and releases them to persons having the proper universal key, but retains the universal key, so that keys can be removed from only one slot by each universal key.