Class is Hussar, Heavy Cav, etc. Unit is the actual unit name. For example, if a team was on france and picke the Cuirassier Heavy Cavalry, then everyone must go the Cuirassier Heavy Cavalry unit. It cannot be four cuirassiers and than one Carabinier. While a Carabinier is the same class tpye, heavy cavalry, it is NOT the same unit.