elongated support wall 112 which is comprised of a front face 113 the front face 113 defines a bottom short edge 114 a top short edge 115 a right long edge 116 and a left long edge 117 the support wall front face 113 perpendicularly extends an alignment wall 118 at the right long edge 116 that runs the length of the right long edge 116 in one embodiment the alignment wall 118 extends from the front face 113 at the left long edge 117 the alignment wall 118 defines a pass through space 119 sized to allow the partition walls 114 115 116 passage through the alignment wall 118 the front face 113 perpendicularly extends a locking block 120 at the bottom short edge 114 that runs from the left long edge 117 toward the alignment wall 118 for a portion of the width of the bottom short edge 114 in one embodiment the distance of space between the locking block 120 and the alignment wall 118 is equal to the width of a cartridge 300 the locking block 120 extends from the bottom short edge 114 and runs along the left long edge 117 for a portion of the length of the left long edge 117 in one embodiment the portion of the length of the left long edge 117 run by the locking block 120 is equal to the width of two cartridges 300 in one embodiment the locking block 120 runs along the left long edge 117 for the.