a lock - box for safely storing a handgun . the lock - box includes a receptacle having an opening at one end thereof and a locking door with a flange for closing the opening . a pair of mounting brackets are secured to each of the opposed sides of the receptacle . the mounting brackets are adapted for sliding engagement with a mounting plate which may be attached by threaded fasteners to a supporting surface . when a pair of mounting brackets are slid fully over the mounting plate , a portion of the mounting plate will remain adjacent the opening for positioning between the flange and the receptacle to prevent the removal of the receptacle from the mounting plate while the door is locked . because the mounting bracket pairs are on the opposite sides of the receptacle , the lock - box can be flip - flopped to suit the needs of a user .