While the conventional module box contained 12 reserve-tanks of car cooling part units, the improved box can contain 15 units, an increase of 25 percent, without changing the box size. Each unit was first rotated horizontally to prevent contacting the other units. A three-dimensional rotation has now been added to contain three more units without contacting the protruding parts of other units. The workability has also been improved by using materials to support the tilted units.