A car turntable, also called a vehicle turntable, is a motorized rotating platform that turns a vehicle in place. It can let the driver leave in a forward direction when a driveway, garage, basement entrance or showroom does not provide enough room for a normal turning path.
It is most useful where the vehicle can reach the platform but maneuvering space is constrained. The practical choice still depends on the largest vehicle, clear entrance, approach and exit direction, available floor or pit condition, rated load, power supply and destination requirements.
A platform diameter alone is not a complete specification. Send the vehicle details and a simple site plan so the usable turning envelope and installation structure can be reviewed together.