You draw in unclean water using the piston, then push it down again, which pumps the water through an ultrafiltration chamber. The chamber contains a special membrane with pores just 20 nanometres wide. That’s small enough to filter out everything from sand particles to minuscule E. Coli and salmonella microbes. The purified water comes out of a tap as safe drinking water. The ROAMfilter Plus is cheap, portable and easy to use. Since 2014, creator Wateroam has provided safe drinking water to more than 250,000 people across 43 countries, including those afflicted by Russia's war in Ukraine and the earthquake in Türkiye and Syria. Watch to learn more.