The Eco Four Twenty is perfect for those who want to reduce smoke in their environment, like smokers in small rooms or public areas. It fits in the palm of your hand, making it super easy to carry around. You simply exhale your smoke through the device. It's made of aircraft - grade aluminum and has a 2 - stage medical - grade filter. The only thing you need to replace is the filter cartridge, which lasts about 500 puffs.