A Dual-Purpose Improved Conventional Munitions (DPICM) is an artillery or surface-to-surface missile warhead designed to burst into sub-munitions at an optimum altitude and distance from the desired target for dense area coverage. The sub-munitions are designed for both antiarmor and antipersonnel attack. Some sub-munitions may be designed for delayed reaction or mobility denial (mines). The air-to-surface variety of this kind of munition is better known as a cluster bomb. They are banned in some countries under the Convention on Cluster Munitions.