Each Tailwind iQ3 module can control and monitor up to 3 garage doors. It ships with 1 garage door wiring kit. To control more doors, just add the appropriate number of door kits to your order. So, for example, if you have a 2 car garage you will want to order 1 additional door kit. If you have a 3 car garage you will want to order 2 additional door kits.