releasable by exerting an upward force on the pivotable locking member 10 referring now to fig4 and 5 an alternative embodiment of the invention employs a locking member 110 which is slidably mounted on the first box member 4 the second box member 6 is provided with a plurality of fixed locking members comprising upstanding l shaped hooks 120 for each hook 120 there is a corresponding hole 34 in the slidable locking member 110 under each hole 34 there is a space 36 as best shown in fig5 for receiving a corresponding hook 120 the proximal 114 and distal 116 ends of both slidable locking members 110 are provided with ferrous inserts not shown so that they are attractable by a magnet by swiping a first long edge 30 of the box against a suitable magnet the slidable locking member moves in the direction of arrow 38 to an unlocked position in which the hooks 120 can enter and leave the spaces 36 via the holes 34 with the box 2 in the closed position and the slidable locking member 110 in the unlocked position the box 2 may be locked by swiping the opposite long edge 32 against a magnet so as to move the slidable locking member 110 to the locked position in the direction of arrow 40 here the hooks 120 are trapped in the slidable locking member 110.