The Isetta is an Italian-designed microcar built under licence in a number of different countries, including Spain, Belgium, France, Brazil, Germany, and the United Kingdom. Because of its egg shape and bubble-like windows, it became known as a bubble car, a name later given to other similar vehicles.
It appeared alongside, and was compared to, the smallest ever car, the Peel P50 in Series 10 Episode 3.
The Isetta bubble car was driven by Iso in a deleted scene from Series 15 Episode 1. It had many flaws in the system, especially when Clarkson ended up trapped inside the car after parking too close to the garage wall, because of the only door being at the front and lack of reverse gear.