the two side pivot latches each single tray 121 includes two end pivot latches 123 one at each end and two side pivot latches 124 one along each side as mentioned earlier each end wall 126 includes a pair of cooperating slots 132 each slot 132 is constructed and arranged to receive a connecting tab 131 of a latch 123 that is attached to the immediately lower adjacent tray 121 in the stack of trays a similar arrangement exists on each side each side wall 127 includes a pair of cooperating slots 133 each slot 133 is constructed and arranged to receive a connecting tab 131 of a latch 124 that is attached to a lower tray 121 in the stack of trays this interfit of the latch connecting tabs 131 inserting into the slots 132 133 of the adjacent upper tray 121 is illustrated in fig2 28 the connecting tabs 131 of the uppermost tray 121 in the stack of trays regardless of the number of stacked trays are used for securing the closing lid 122 for making the stack of trays a case the connecting tabs of all other trays excluding the uppermost tray in the stack are used for connecting adjacent trays together such that the entire stack of trays becomes a single.