The stopping power rises in symmetric sandwiches with increasing explosive layer thickness, which is equivalent to higher plate velocities. Further the additional weight is a burden for add-on armor. Therefore a study was made with very thin sandwich plates of 1 mm as more or less the minimum, what can be used in practice. The reduction effect is more reduced with thicker plates at constant explosive layer thickness. For the penetration reduction the product of plate thickness and plate velocity seems important, as a thumb rule.