Compared to the past, magnetic stripes have evolved and become more resistant to magnetic fields. In normal use, there is no problem even if they are stacked on top of each other. In addition, IC chips are not affected by magnetism, so there is no problem with stacking them. However, bank cards with no expiration date may have weakened magnetism, so we recommend that you stack the magnetic stripes in alternating positions, for example, top and bottom.