According to the WHO, around 35-40 million people worldwide need leg prosthesis to enable them to move around independently of outside help. About 80% of these people live in countries with a low average income. Only one in ten affected persons has sufficient financial resources to purchase such a prosthesis. Against this factual background, Project Circleg was initiated by two young Zurich industrial designers with a keen interest in social design and plastics. The project, now driven by a core team of eight as well as numerous external experts and supported by renowned institutions, combines a classic industrial design task – the development and design of a functionally convincing leg prosthesis – with a social concern and a circular economy approach. The high-quality Circleg prosthesis system is made of a reinforced, recycled plastic and is characterized by low weight and good wearability. Its modular design allows for customization and easy replacement of individual components. All components of the prosthesis can be easily recycled again. Regional structures are used or established for the production and distribution of the prosthesis. On the one hand to keep production costs low, on the other hand to avoid long transport routes. Circleg is currently working with partners in Kenya on the implementation of series production.