It is not a convertible. A convertible has wind-up windows in its doors and may be converted from open to fully closed. A convertible is by nature much heavier. Side protection may be supplied to a phaeton by clipping on flexible sidescreens where there are no windows. Phaeton bodywork is by its nature much lighter than convertible bodywork or a sedan and so it is suitable if speed is important. Because the body was entirely open it was easy to add or remove an extra row of seating where space had been left in the original construction.