Fontus is a self-filling water bottle for your bicycle. If you´re a cyclist, you know the anxiety that comes with running out of water in the middle of a bike ride. The last thing you want is dehydration when you´re miles away from home! This device collects the moisture contained in the air, condenses it and stores it as safe drinking water. Powered by solar cells, it can harvest up to 0,5 l water in an hour´s time under the right climatic conditions. Harvesting water from the air is a method that has been practised for more than 2000 years. The Earth’s atmosphere contains constantly around 13.000 km3 of mostly unexploited freshwater. This project is an attempt to discover these resources. Fontus can be applied in two different areas. Firstly, it may be interpreted as a sporty bicycle accessory. Useful on long bike tours, the constant search for freshwater sources such as rivers and gas stations can cease to be an issue since the bottle automatically fills itself up. Secondly, Fontus was originally invented to bring an alternative way of collecting safe drinking water to regions where drought and unclean water are a big issue. Bikes, as the most widespread means of transport in the world, especially in developing countries, seemed to us as the perfect vehicles to combine with this invention. Fontus might be a clever way of acquiring freshwater in regions of the world where groundwater is scarce but air humidity is high. It could work as a mobile water well, for example, providing a child with water for the day while riding to school. We conducted a series of experiments trying to identify the ideal conditions, materials and cooling systems. We simulated different climatic conditions, modifying the air temperature and humidity.