An armor module comprising a rigid casing having a front face, a top face and a bottom face, and a plurality of multi-layer planner cassettes fixedly mounted within the casing. Each cassette has a top base plate and a bottom base plate, sandwiching between them at least a one other layer. The top base plate of an uppermost cassette constitutes the top face of the casing, and a bottom base plate of a lowermost cassette constitutes the bottom face of the casing.