The M577A1 Command Post Vehicle, also known as the M577 Command Post Carrier, is a variant of the M113 to function on the battlefield as a mobile command post; that is, a tactical operations centre, usually at the battalion level. The M577 saw operational service in the Vietnam War and more recently in the 2003 invasion of Iraq. It is also used as an armoured ambulance, emergency medical treatment vehicle and fire control vehicle. It is also used by various police forces and law enforcement agencies as a tactical response vehicle. The M577 is easily distinguished from the M113 upon which it is based by its raised upper hull and roof-mounted auxiliary power unit (APU). The kit comes with a driver, engine and rear compartment details.