In order to be considered in supply, a unit must be within 20 movement points of a supply unit that is part of a supply chain. Unsupplied units are unable to move or attack, and defend at half strength. Supplied units can move and defend normally, and attack at half strength. Units within 8 MP of a supply unit receive a higher level of supply, and can attack at full strength. By expending a supply unit, the combat strength of units within 8 MP is temporarily doubled ("Maximum Attack Supply").