Since its debut , Kettler has made many different varieties of the Kettcar and has sold more than 15 million of them worldwide .
The Kettcar , however , has four wheels and requires no balancing to ride .
Since Kettcar 's debut , Kettler has made many different varieties of Kettcar Kettcar and has sold more than 15 million of them worldwide .
The Kettcar , however , has four wheels and requires no balancing to ride .