Dual controls are a set of pedals on the passenger’s side of the car, in addition to the regular pedals on the driver’s side.
Dual controls allow the passenger, normally a driving instructor, to stop the car using the extra pedals.
If it’s a manual dual control car, there will be two pedals on the passenger’s side: brake and clutch. If it’s an automatic dual control car, there will only be a brake pedal.