In some army lists, certain units will have the option to be accompanied by up to two smaller support units known as 'detachments'. Such units are known as 'regimental units' and are marked by having the 'Regimental Unit' special rule. Units that can be taken as detachments are marked by having the 'Detachment' special rule.

In some cases, a model may have both special rules. This simply means that a unit consisting entirely of such models can be either a detachment or a regimental unit. It cannot be both, however, and you must ensure it is clear when writing your muster list which rule the unit will use (if either). You should also ensure this is made clear to your opponent during deployment.