What feature characterizes a folding camper?

A folding camper is characterized by its collapsible sides, which allows for easy transport and storage. The design typically includes a frame that can be set up and taken down quickly, making it versatile for camping or recreational use. The ability to collapse the sides helps in reducing the overall size of the camper when not in use, facilitating easier handling and reducing the footprint when parked.

In contrast, features like a fixed roof or hard-sided walls generally apply to more traditional or fixed campers. These features do not promote the portability that is central to the concept of a folding camper, which is designed for flexibility and convenience. The extruded aluminum frame, while it may offer benefits in terms of durability and weight, does not define the folding nature of the camper itself. Hence, the collapsible sides are the defining feature that distinguishes a folding camper from other types.