Traditional mask filters use meltblown fibers that take advantage of static electricity to pull particles out the air as it passes through. Masks that use this method cannot be washed and re-used since washing them removes that static electricity, causing them to become poor air filters. The Rethink filter is fundamentally different and is instead made up of incredibly small nanofibers that are packed densely together to form a microscopic net that catches and blocks small harmful particles, such as bacteria, viruses and dust. The real magic begins when you want to re-use the mask a second time. The Rethink filters do not lose their ability to filter when disinfected, so they can be reused up to nine times simply by disinfecting them in boiling water after each use.