The basic set contains all the components required for the initial installation, including a voltage transformer, cabling and switches.
The extension kit is designed for vehicles in which the basic electrical installation is already in place, having been fitted with a Comfort Lift. The extension kit therefore allows a second Comfort Lift to be fitted in the vehicle and connected to the existing basic electrical system.
You can obtain the Comfort Lift to suit your vehicle from your nearest dealer. You can find an overview here: To dealer search