Each army division has a headquarters (HQ) unit and three combat brigades. Two of the brigades are Infantry brigades (with a high proportion of infantry and artillery, with only light tanks) and one brigade is classified as Armoured (with a high proportion of heavy and medium tanks and fewer infantry and artillery). The HQ unit is mostly used to resupply the other three brigades, and is vulnerable when placed on the front line by itself. It is common practice to attach the armoured brigade to one of the infantry brigades and use the HQ unit to resupply both.