This is achieved thanks to the SODIS method of water purification whereby PET bottles filled with water are left in the sun in which the sun’s UV-A radiation will kill the majority of germs in the water, rendering it relatively safe to drink. Unfortunately by using PET bottles, this process will take about six hours to purify 3L of water, however with this prototype device, its creators are claiming it will be able to purify 9.4L in the same amount of time while carried about. No word on when we can expect this solar bag to be manufactured and provided to developing countries around the world, but it certainly is a pretty exciting prospect.