4wd slotFor the rest of us mortals (!) the Slot.It belt driven 4WD is a good compromise. It's available on the Audi R18 and there are also compatible chassis for the Scalextric short wheelbase Quattro and the Delta S4 available throughOn its Audi R18 e-tron Slot.it has created a 4WD system which is truly unique and innovative. In the Slot.it system, a toothed belt provides power to the front axle through two micro pulleys which are coupled to the left wheels.